I had already written a review for the first season of Strike Witches. You can find it here: http://www.anime-planet.com/users/ForTheLoveOfLoli/reviews/12186
In reviewing Strike Witches 2, I will use what I have already stated in the review for the first season, as a starting point. This is because, honest to God, nothing about Strike Witches 2 has changed significantly from the original. I will trust you have seen season 1 if you're going to watch this. This will allow me to keep the review quite to the point.
Probably the greatest difference between the season is the geographical setting: not the skies above the UK, but Italy this time.
Yes - it's all the same crew of teenage Witches fighting the same alien enemies in the same way. Again, each has their own internal or interpersonal struggles to overcome, that aren't much different from last time. Hence, it does not greatly help in further developing the characters, and they remain rather cliched, however charming. You do hope they will all continue to go along well.
The humour is also exactly the same, and wasn't the series' strong point to begin with. Yoshiko and Co. engage in the same panties-and-boobs ecchi and strong yuri innuendo, with even greater enthusiasm. There is some friction with broom handles and Neuroi bugs - any excuse for crotch level ecchi comedy is taken, if it works (and if it does on your laughing muscles or, uh, some other), depends on the viewer. For me, meh.
And again, the incompetent, selfish and corrupt military elite prove to be an even greater enemy to our Witches of the 501st Joint Fighter Wing than the Neuroi are. This does not provide any major plot twists, however. And my greatest disappointment was that the big plot hole left in the first season - about the neuroi perhaps being friendly and wishing to communicate - has not at all been patched, even though S2E1 gives a good hint that it might be. Alas. The chance is ham-fistedly abandoned, seemingly without reason.
It all remains on the surface. At least, there's still the action scenes and weapon designs that are very well done. And some of the girls, sure, are cute. I can't really torch the anime, but after Season 1, this second season did get tedious in the end for me.
I'll give it a 5 out of 10.