When I was collecting trophies, I ran into a wall at 500 trophies. I wouldn't get any new trophies anywhere. Recently, I started clearing all-star mode with all characters, and suddenly all sorts of trophies are dropping. Even in the trophy store, I'm getting 4-6 new trophies every time I check in.
Is this a coincidence, or can anyone confirm that playing all-star with various characters yields different trophies?
Somewhat related to this question, I noticed that the characters I've played the least, have the lowest amount of unlocked custom moves and equipment.