I can't really speak for Kaim, but as for wanting to have the sequel on the same platform there are valid reasons. For one, sometimes a developer will have a game check the system for save files for previous games, and adding bonuses if found. Or it could be just for collections sake; preferring to have a series of games match up on a single platform.
Personally, I'm still picking up Agarest War Really Naughty Edition on the 360. I'm hoping there will be enough support for both platforms so that the developers can continue to work with the series.
Heh... well, if Aksys really wanted to impress me, they could start licensing Sakura Wars 1-4... now THAT would be a VERY good investment, IMHO. Unless NIS beat them to them. I just want to see them ALL over here.
I'd also like to see Aksys up the combat to stop making the battles so... repetitive. It seems like the only thing you do is go to an area, fight... go to another area fight or explore and then fight... Sensing a pattern here? That needs to a little more than that in order to peek my interest. The first game has so much potential but the idea of only beating enemies 3 or 4 at a time by going to certain spaces is like a bad board game repeating itself over and over again.