I think Scorpion Engine is a great thing and pretty good optimized if I look at releases like "Phantom Leap" and so on... doesn't look very "limited" to me. :-)
Limited in a sense that all the games look the same... when it comes to the mechanic and etc. I think this is the biggest issue with scorpion right now - You cannot do super customized games with that like If you would program everything by yourself. Understandable.