Well, personally I like getting tons of new dragons, but I agree it can get a little out of hand.
More farms would be nice too, but they take up a lot of space. I'm thinking another "upgrade" of the farms would be great, especially for high level players. Three new crops with a very high cost and yield to use up all those coins! Back when I was at a lower level even the Upgrapes, Rushrooms and Diamondates were almost impossible to get...