I am surprised to be the first one to add a review and no I am not ashamed to review before the anime ends, there is no need to wait.
Its...not that good. Especially for somebody who really likes the original novels, manga and anime before.
What happened? I think every problem this series have is pasting issues. They simply try to fit so much stuff in to the episodes which forces them to cut needed character development. It also forces them to put exposition more in to dialog and Touma looks more stupid and boring then he does in the light novel, by far.
They are faithfull to the material, but lacklaster. It all feels like just "make it as it is written, don't think about it much, just do it... first take and let's move to some bath scence!"
What they did change, or rather cenzure was the moment: SPOILER
When Misaka realizes that she loves Touma. It happened generaly very similary, except Touma wasn't tired looking, but covered in blood and brusies, he was barely not passing out with electrotes from the hospital machine still on his head. When she saw him she didnt went completly dere, she was worried, confused and then as he left she figure it out, LITERARY changing her personal reality. For those who don't know that is what makes her ESP powers work and changing that can change the ability! That impactfull... did it feel like that i the anime? Not by a long shoot.
I really enjoyed this season. I just do not like how rushed it felt. They were throwing in a lot of stuff, and it got confusing at times. I don't feel like all of the characters were fleshed out that well. Overall though, I liked this season, and I am hoping that they will continue it.
The first two series were pretty decent, and I enjoyed both of them. Index III is a tangled mess that should have never been made, at least not in this form. It could not be more obvious that they tried to adapt far too much material while keeping the episode count as low as they could.
The result is a confusing, incoherant plot that seems to skip many necessary details that would have at least let someone who has not read the full series follow along. Characters are introduced and then dropped with little explanation, and most of those that stick around don't really get any actual characterization. The series goes from the Touma-show to the Touma, Accelerator, and other guy show; and while I like Accelerator as a character, the series never really gives a reason to empathize with the other guy so the multiple plotlines just makes it all feel bloated.
And I do have to question why they decided to change the sound effect when Touma's right arm cancels out a power or magic. It seems a needless change and makes it inconsistent with the two series that came before. This may seem a silly thing to nitpick when the series has so many other flaws I could write about, but it genuinely bothered me in all 26 of the episodes when I heard it. Surely there were more important things they could have focused on to make this series more... well, more?
Viewers who enjoyed the previous two series should watch this only if they have fully read the remainder of the light novels; maybe then they could get some enjoyment from it. If not, they are liable to finish the series feeling confused and disappointed; this franchise deserved a better ending than this.