You haven't played it...you're judging just for one review. And besides, that was a port. One thing is porting what you've made for a system with 4.7GB storage medium to other with 1.8GB medium, and other thing is directly making a game for those 1.8GBs from the ground up. If Atlus can fit Devil Survivor properly in just 64MB, there's nothing to worry about
After all, just look at BBS...does that look like a raped KH?