Two points on the Infinity wargame:

1) Women’s body armour is a different shape to men’s, and does tend not to extend as low, due to different body shapes:

http://www.policemag.com/Channel/Women-in-Law-Enforcement/Articles/2007/10/The-Shape-of-Womens-Body-Armor.aspx

So the midriff-baring look is… still kinda silly — but not totally.

2) More pertinently, the entire game is inspired by an anime/manga aesthetic. That’s one of their main selling points. Whether that look is inherently sexist is probably beyond the scope of this comment, but that consideration is still necessary before judging Infinity too harshly, I think, and certainly anime & manga are arguably more appealing & accessible to women than are most other ‘geek’ pastimes. Anime & manga fans make up most of the game’s target market, and the “sexy” minis are some of their most popular.