Awesome guys, thanks for que quick answers ! I tried a bit Sengoku Rance yesterday, seemed fun, but I didn't understant half of the way to conduct battles =D. Gonna spend more time on it if you say it's great !
And if I may ask for another advice, do you know any nice game, without too much grinding, and more importantly with no hentai at all. My little sister would love the concept, except for this part =).
Edit : @Kaguya : My conception of game oriented means mainly optimisation. I want to be in a situation where I have to think and to play cleverly to win. And if it's too hard, I can always do something to better my troops / characters.
Edit - Bis : Actually one of my all time favourite game of the genre (not of VN though, but not that far) is Disgaea, which is well... Incredible, great humour, tremoudeous possibilities, great gameplay, etc. Of course I won't be able to find a game this deep, but the idea was to exchange a bit of the game part for some VNization.