The best thing about Spore is Creature Creator. When will they realize this? I could care less about the actual game. I've spent more hours in Creature Creator than I have playing games like Mass Effect.
The most disappointing thing about Spore was that it never delivered on the promise of playing with your Creations. What you created was basically only used as scenery for gameplay that was in no way unique. (who makes a game about reproduction/evolution without sex anyway?!)
I'd happily pay money for an expanded "Creator" and a sandbox. No gameplay mechanics needed.