I think we'll get 2-4 more dlc before the game is ignored in terms of dlc characters.
Reason I expect this is because its 5 dollars per character, I mean 4 dlc characters alone is half the price of the full game. I don't expect do see dlc equal to the price of the full game (meaning 8 dlc characters)
$5 per pack (if it was this) would seem fair imo but per character in my opinion its not. If sony release all dlc character free the first week then I probably wouldn't mind so much but they wouldn't make money like that probably
I predict 3 more "packs" (2 characters and a stage) --- Jumping Flash!'s Robbit needs to be in Playstation All-Stars as DLC! Sign the petition for him here: http://www.petitionbuzz.com/petitions/robbitfirstallstar