Senran Kagura has barely-covered nudity and lots of clothing damage, but no, none of the girls are second graders, they're all in highschool...
Also, unlike games like those, Senran Kagura has no male love interests; the only male characters are older, and there isn't any romance between them and the girls. In the anime for instance, the only hints of romance were between the girls. And the girls can protect themselves quite well, and are the playable characters too; no "guy rescues girl" stuff in Senran Kagura for sure, games or anime. So yeah, it's got vast amounts of visual fanservice, but in terms of the story and writing, the anime particularly was actually good. It was a fun, cheesy series (power of friendship!). I liked it. I know that the games have lots more fanservice than the anime (lots more), but hopefully they're as good as the anime was...
If XSeed can manage physical Vita releases, I'm sure they could do more physical 3DS games if they cared to push for them though.