There's not a moment of aiming and shooting it's purely placing your team and chose actions. Turn based.You won't find the turn based FPS gameplay, but if you and settle with turn based strategic grid based games - then there are quite alot!
Its not FPS, its not even an TPS, its just that you controll soldier with stick, not cursor, you got to think, not to shoot fast and accurate (since you can aim as long as you want).
Something that resemles that is some way was in Sakura Wars: So Long, My love, but there you slash your enemies, not shoot them. Great tactics/datesim game nevetheless
First time I'm encountering Disgaea I'm looking at reviews right now. Thanks man.There's a game called operation darkness for the 360 that's similar, but whether you'd like it or not, I'm not sure. The X-Com reboot is a little more traditional than valkyria but the combat is still good. It's not exactly what you wanted, but the disgaea series is one of the best in the srpg genre, with depth and customization unmatched by any rpg ever.
By the way the first disgaea game is available as disgaea DS.