Crash died in popularity when they changed the formula that worked. 3D platformer with 2D aspects. Something nintendo have just used on Mario 3D.
Crash Bandicoot 3 was the best platformer around until SMG. It had fun platforming, it had a variety of locations and enemies. It had power ups. It had comedy. It had time trials. It had bonus levels and it had varied gameplay (standard platforming, running through with a bazooka, doing a bike race, etc)
Crash 3 was the peak in the series, Wrath of Cortex sold really, REALLY well and even Crash Twinsanity (best OST ever) was great. They killed the series though when they decided to change Crash AND the general gameplay with Crash of the Titans.
If a real 3D/2D Crash is developed by a team who actually know how to make platformers, then Crash can eventually return to being a multi-million seller.
