Considering the game struggled to run on multiple systems at release I would say it's an optimization issue. Most studios start development for the latest and greatest in hardware and then try to pare it down to run on less powerful systems, or I should say struggle to pare it down. I like Capcoms approach better. Develop it for the least powerful system first and then scale it up. I believe with that approach the game will actually be playable on future hardware or be more easily ported to future consoles
