After growing accustomed to what the world development team is capable of in the latest released worlds, I've started thinking that several of the tree models available in housing could use a little more work.
Red Leaf Tree - leaves extend way too far off the branches and need to be scaled back, and there's one leaf "cluster" at the top that just hovers off in space by itself, not connected to anything
Small Snowy Pine, Snowy Pine - the trunk is humongous compared to the branches, looks a bit awkward
Maple Tree, Summer Tree, Cherry Blossom Tree - good texture work, but these trees basically just have two leaf domes stacked on top of each other; it looks unnatural
I realize these are older tree models. I think that makes it even more important to keep them updated though.