A lot of pressure was on Geek Toys this season to make up for the mistake J.C Staff made that was Date a Live Season 3. And for the most part: they did a mostly passable job.
There won't be direct spoilers in this, just enough details to explain what they did good and bad here. So if you're on the fence about giving this season the time after season 3 left a bad taste in your mouth - you can read this without worry for ruining your watch experience and make a decision whether you want to dedicate time watching this from there.
Story: We pick up right after the speedrun that covered the 12th light novel in the final epsiode of season 3 (no retcon episode for that, sorry for the fans who were hoping for that to be fixed. But it probably was for the best just to keep moving onward instead of wasting time backtracking). Shido goes back on his quest to help more spirits, and it pretty much follows suit on how they series has always gone. The twist in the plot starts to emerge as the first arc ends and we finally learn the intentions of the main villain, Westcott, and what he wants with the spirits after 2 seasons of knowing barely anything about his sinister plot. In the 2nd arc we get to see 2 unexpected characters return for a brief spell, some more information is slipped through, and then it ends in similar DAL fashion. The 3rd arc... is where DAL goes into overdrive: the Kurumi arc. We finally learn the story of Nightmare and how she ended up as a spirit. We learn of the final boss of series, and a twist on par with Kotori's reveal as a spirit in season 1. I won't spoil anything, but all I'll say is: DAL has approached it's Endgame, and with Season 5 now confirmed we now sit on the edge of our seats to see the final act.
While there were a fair number of distractable slice of life episodes in between all the action, this isn't far off the course that the series has been doing throughout it's runtime. It's just become more noticable now that there's a darker, more interesting theme approaching and its being interrupted by all the s.o.l shenanigans. While I understand it can be bothersome, it didn't derail it enough to be harsher about it.
Also if you still didn't get enough Love is War in your life even with it's latest season going on then you'll love this last arc in particular - you'll understand why.
Consensus: solid story that's continuing the escalation setup by last season, kept me interested despite being interrupted by a number of s.o.l episodes, and has set the stage for it's next season to be the climax of the series.
Art/Animation: The new art style divided the community to some extent. Of personal opinion, I liked the character remodels and vibrant colors that gave so much more detail and life to the cast and background art. Though I understand why other folks don't, it took a lot of familiarity away from the series and no longer matches the illustrations of the source material. And I admittedly do miss that a bit. But it was universally a step up from last season's trainwreck deviantart level style, so the general impression I've seen is that it's gotten at least a "pass" from most the fanbase.
But even without the artstyle debate, a far bigger problem quickly emerged. Moving to the case of contention within this season: The CGI fights. Ima keep it real with you chief, at it's best it wasn't pretty; and at it's worst it was just awful. The rough transitioning between 3D puppets to still frame 2D action shots as they collided didn't look good. The Origami vs Inverse Tohka fight was supposed to be one of the most action packed moments of the season: it punctuated the OP of this season and from that it looked like it was gonna be great. But after waiting 8 episodes for this promised hyped up fight, we instead got essentially 2 plastic action figures bashing into each other with only the hands of the kids holding them edited out. The space fights with Mukuro particularly were extremely awful looking. It's no exaggeration to say the animation is worse than season 3's, but I'd even go as far and say that it was so horrible it could be on par with the likes of Arifureta season 1 - that's how bad it was. And if you've seen or even vaguely know of Arifureta's reputation regarding it's animation: that should upset you immensely. It is by far and away the biggest complaint about this season.
There was also the unfortunate factor of censorship sewed in as well. I don't care that some of the echii was diluted down (that was expected), but the darker parts of the story were significantly changed to be less gruesome - to the point where it changed entire scenes brought down the weight of the final arc (Nibelcole and Shido's room scene for example). LN readers have been very vocably upset about this particularly, and I agree with them.
Overall, for the 2nd season running animation was by far the weakest element. Like season 3 it wasn't unpassably bad to kill the anime, but by God it was awful. The eye-capturing action that makes DAL so unique and special from other harems was butchered badly this season. The only thing saving this grade was that the 2D elements looked better than before, and they put a lot of effort into making the background and fine details look much better. But why wasn't the most important elements and action scenes given as much care? Geek Toys needs improvement here: Badly.
Sound: While it was dissapointing to have the tradition broken and not have Sweet A.R.M.S do the OP, Miyu Tomita did a pretty good job and still gave another equally banging one for this season. As far as background tracks goes, they mostly kept up with properly matching the tone of anime and it's scenes. Now we didn't get many new tracks this season, but tbf they had already been doing Date a Bullet and we heard quite a few of those throughout the Kurumi arc - so I'll give them a pass. My only dissapointment comes from not having an orchestrated version of the OP in the final episode as we've had in the 3 seasons past, but it's basically nitpicking of a hardcore fan at this point.
Voice acting remains solid, on the original japanese end. I'm not gonna factor this into the grade at all because it would be unfair and is irrelevant to anyone who doesn't watch alternative versions/dubs. But in case you don't know the English dub has had some problems of securing some of it's original voice actors back for every episode, and there's been an almost merry-go-round rotation between some characters sounding notably different in the dub across episodes as they've been using different voice actors. It's a jarring experience and has actually turned me off from watching the dub for the time being. Likely gonna have to wait till the DvD releases in August to hopefully get the version where they've got the whole voice cast back and recorded for every episode.
But back to point: disregarding the dubs problems, overall sound/music was great - still the series' best and most defining aspect.
Characters: I'm not gonna pretend that DAL doesn't have the problem that most harems have as they keep growing in size of sidelining less relevant characters in favor of the ones that are the focal point of the plot - because we all know it's absolutely guilty of it. Yoshino, the Yamai's, Miku, and Natsumi were benched for the majority of the season, bar a few specific scenes where they got some crumbs for attention. And Kotori remains in the same logistics point of directing the plot she always is in. Some points are gonna be docked from this category inherently. That being said, this isn't a new problem for the series (or the genre in general) so you just learn to go with it and focus on the "main" returning characters to develop or take part in the plot in a notable way. Which were: Shido, Tohka, Origami, Kurumi, Reine, and the villains Westcott and Ellen.
For the new characters of note from this season: We have our 2 new spirits Nia and Mukuro, the new DEM adaptess Artemisia Ashcroft, Nibelcole, and the final boss of the series... the Origin Spirit.
Of the 2 new spirits, I liked Nia the most. She broke the mold a little bit being that she wasn't some oblivous, innocent girl that Shido easily charmed into liking him like most of the cast. She's an older women in her 20's who's confidence, lack of a filter, and awareness of exactly what Shido is trying to do put him into uncomfortable, less cliche and more interesting situations - which was very refreshing. It got a few genunine chuckles out of me and I was interested in seeing where her story goes. She does get mostly sidelined sadly after her arc ends, but that is the series for ya.Next up is Mukuro, who falls back into the tropey nature that most of the DAL girls fall into: innocent girl that nearly immediately falls for the MC, but with another gimmick. Personally I found her very uninteresting, though I can see why some fans would like her - she is pretty much a cupcake in both looks and in personality. My distate in her could be attributed to her arc being dragged out for far too long, and having had Nia's arc just prior to hers which I enjoyed a lot.Artemisia takes the place of Mana and Origami as the head AST that follow's DEM's commands. There's apparently a lot more to her, but from what I've been told from light novel readers a good portion of related backstory and scenes involving her have been cut. So for the time being, she left extremely underdeveloped and she kinda drops off from the story after the halfway point. Guess if you want more information on her you'll have to read the light novel... but given that it's expected to be an estimated 2+ years as of writing this before it will get officially brought over in english - it's gonna be awhile unless you go to an unofficial translator. :/Not gonna explain who Nibelcole is as well as the Origin Spirit, doing that without spoilers would be too much giveaway. All I'll say is that Nibelcole was notably watered down in brutality in the anime, as I've seen some of translations from the light novel about some of the things she was supposed to do in a few scenes... look up at your own discretion.
Tohka and Origami get their time in the spotlight in the Mukuro arc, but in an unconventional way. Again, don't want to spoil - this review is intended for folks sitting on the fence after going through season 3. Westcott and Ellen's plot starts to unfold, and they get a lot more screentime. Mana is back after being gone for the entirety of season 3, and that's nice - but she doesn't do much in the grand scheme of things here other than show up in a couple of scenes. Reine gets more involved in the plot and we see more of her this season. And Kurumi... is once again, the biggest attraction. Her arc is the reason DAL has skyrocketed to the top of almost every poll in the final weeks of the season - and for good reason. And Shido starts becoming more aware of his purpose, starting to ponder the nature of what he's doing and why.
While many characters were sidelined and might as well not exist and Mukuro's arc might've been a bit slow, the ones that got focused on were for the most part pretty well written. Nia's arc, as well as Shido and especially Kurumi's development carried this season.
Overall: I can feel comfortable saying that Date A Live IV was definitively a step up from 3 in terms of it's production. While it definitely still has its issues, the end result was still roughly enjoyable as each one before it. Subjectively, DAL is one of the best harem series ever made and is still manages to be my favorite guilty pleasure anime of all time. It would take a truly awful season to change that, and thankfully this wasn't it.
We'll see if Geek Toys breaks the curse of every studio only doing 1 season of DAL before passing it along to the next. But if they do, and you happen to read this Geek Toys: I want to first say I appreciate your work towards adapting this series and picking it up from where J.C Staff abruptly dropped it. But please, Step up your CGI. Every fight made in 3D this season, bar the airship battle, was horrendous and by far the biggest thing that really held this season back.This is a very fixable problem that I hope they recognize and put effort into fixing for next season to make a finale worth the years of build up and waiting.
Overall, Solid 7 out of 10 anime/season - with a .5 bonus for personal enjoyment/bias for the series. It would've needed to address some of it's issues listed above in the animation and character sections particularly for it to reach an 8 or higher. A definitively better showing over the previous season, but it had the potential to be so much better.
Edit 6/28/22: To address as someone has pointed out, there are some changes we have gotten from the DvD releases that have fixed some animation problems in the past (notably season 2). If we do get significant changes from the DvD release that fixes enough of the horrible CG we had this season I'd be willing to come back and reevaluate my grade. While I genuninely hope there would be, ngl I think its unlikely. Looking back on S3's post-broadcast changes for instance: they were extremely minor and didn't change the fate or grade of the overall product, just slightly polished up 1 fight scene and the rest were pretty much un-noteable background touch-ups.
The DvD releases in mid-August, so I'll revisit this - as well as the dub (hopefully they get all their original voice actors brought back to fix the consistency issues) once it comes out with the Uncut version. Until then: this grade stands as it's all we as an audience have received.