Maybe just a LITTLE *too* much
9 points gained for flexibility of development. 1 point lost because the game doesn't challenge you to master more than one or two styles of play. I don't pay much attention to what kinds of gems I'm using; I find I'm too busy gunning down waves and keeping the next wave coming to tweak up my score. Which is fun, but...You can play slowly, and play with the different kinds of gems; but it's not neccesary, and people going for the highest score will (I think) more often than not miss out on the gem creation system.
ALSO: WHY did you guys decide to make gem creation RANDOM? I understand it creates a lot more potential for diversity (still not sure exactly what "hues" are), but it also discourages strategic planning. And if your reasoning was to avoid people using the same gem type over and over (I always go for AoE towers), then the problem is that the gems aren't balanced against one another, and it should be addressed as such.