Pro: They sell more copies meaning more chance of further entries in the series.
Con: Playing it on easy completely misses the point of the game. The people who complain about the game being too hard are brain dead. They don't want to learn. They don't want to be taught. They don't want to accept that the reason they keep dying over and over again in the same place is because it's their fault, not the game's. They just want to barrel into every encounter mashing a button and hoping for victory.
Personally, I say let 'em have their easy mode. I know that I'll be a lot more satisfied when I complete the game the way it's meant to be played than someone who needs their hand held. I just hope they call it 'Queenie Mode' or something similar and I really want them to offer no trophies or achievements for anything in easy mode. It'll also be interesting to see how they handle the online functions. Griefing the easy moders will be fun if it's allowed