Dart from Legend of the Dragoon.
LotG was the FIRST turned based RPG to ever hit the PS series. It was the only game in the PS series to come with multiple disks. Dart, along with Spyro, Crash, and Sir Dan were the founding fathers of the PS series. As such he deserves a spot among the All-Stars
Alex Mercer from Prototype
Now Alex Mercer seems like the perfect fighter for All Stars. He has the brute strength to go toe to toe with powerhouses such as Kratos and Sweet Tooth, but at the same time the agility to keep up with agile characters like Sly Cooper and Cole ((ppl can also settle the age old question of who would win in a fight between Alex Mercer and Cole))
Now some people may point out that Alex Mercer is not PS exclusive .....well neither is Big Daddy but yet there he is..
Feel free to add to this list