Rumor mill was they intended cross-platform play and the systems at the time couldn't keep up, frame-rates became unstable and they had to scrap the idea - but move to something more accessible for console gaming at the time. This is also why BL(pre-sequel) will not be on nxt-gen systems. It's designed for PS3 & X360 specifically to work with their hardware sets. It's not even a new code, it's just BL1&2 engine with updates. It would look extremely sub-par on new systems and people would complain loudly that their spiffy new systems are playing outddated looking software. End of the day, each their own.