I was thinking if it could just help with load times between matches and in the Endurance Rounds, and maybe increase frames of animation if they were cut. Only other thing that might be nice is restoring the original attract sequence if possible:I think the RAM cartridge won't help. Files with data of fighters from MKT take up quite a lot of space (300-500 KB each file) and all of them will not fit on the cartridge. If we are talking about the problem of loading characters during the transformation of Shang Tsung of course.
Shang Tsung I don't think would work properly unless you had a massive RAM cart or just put the whole game on a ROM cart. Maybe you could either compress the data or have a buffer kind of system set up if Shang Tsung is being used? So you have the next few morphs buffered in the RAM Cart and as the player morphs through the buffer you keep streaming new ones in off the disc. Not sure how possible that is though.