I agree. This is too soon. I doubt the "exclusive" PS3 game we see from Sumo this year is LBP 3. LBP 2 still feels fresh and new to me.
Again: the game would be at least a year off from when it gets announced (which it hasn't). LBP2 came out two years ago. If it's happening, that is.
Not that I really like how Sony is milking LBP franchise now, but still, this game can be very good and innovative.
There are 2 PS3 LBP games, a kart racer, a PSP game, and a PS Vita game (which is he best of the bunch, imo). That's not so bad, considering it's been around for about five years.