Memory is the smartest thing in this game. With 4 guys, having a character able to access a ton of abilities on the fly would kill character variety. Why bother making a buffer if everyone can buff themselves? Why bother setting up character synergies when everyone can just cast all the right stuff on themself? That's what happened in Original Sin. Without memory, character specialization would fall apart, and it's even more important for it to be a thing when there's 4 characters instead of 2.
