I was watching something on youtube of Shaolin Monks, someone used the cheats to play as Kintaro, Reptile, etc
Anyway.. I think it would be really fun if you had a wider selection of fighters to choose from (obviously). It would be much better for co-op play so that way everyone has a wider selection.
But it wouldn't just be good guys, you could play as bad guys too. We already know the stories of MK (if it were a prequel like MK:SM) so it would just be fun to have like 10-12 different characters to choose from and play through a new story set sometime between Deadly Alliance and Armageddon (since all of the characters are avaiable)
Possible characters I'd like to see would:
Liu Kang, Raiden, Sonya, Jax, Kitana, Sub-Zero, Kenshi (with sword)
Shang Tsung, Quan-Chi, Reptile, Baraka (with blades)