I think a lot more achievements and 'stories' should be implemented into the game. At the moment, compared to many other games, there's not much driving u forward! It can almost seem tedious! It is a Story game after all. We need something to make it feel a bit more, living. Like we MUST get back to it.
U could new Game Centre achievements, but tie them into the game. So each one we get, we earn 1 gem or something. I'm talking, a nice long list of FUN things to do, with good rewards! (ie not bake 60 times and receive 5,000 coins!)
There's a couple of games I've played recently that, even if u were at the biggest level, would still have something to keep u coming back. The only reason I come back to Bakery is because I've got so much XP, I want to keep it going in case there's a level cap update, and in the hope there's fresh new ideas implemented. :-)