Yeah I guess that's always going to be a tradeoff, simplicity vs. functionality. For new behaviors I think there should be more UI behaviors. In the game I just finished using pre-shipped behaviors, most of the custom behaviors were UI related. I use pause and reset buttons often in my games, so maybe those could use a pre-shipped behavior like the mute button. Making an easy to use level locking and saving system would help new developers, but I'm not sure how that would be done. I noticed the score behavior uses a set of custom blocks, so maybe the level locking/saving could be done like that.