Well, it's not that you have plants that bothers me. It's the fact that they're never aligned proplerly. Just like the dilemma with your Pokécenter/Mart. They've always got to be on the same row.
The transition between metal and wood is too abrupt. There needs to be some kind of a barrier. Ever notice in real life, when a floor goes from carpet to wood, it has that wooden or metal ridge. I can't actually remember the name of it, but it smooths the edge of the hard tile and makes for a more pleasing transition.
As for the black, it in no way is choppy. As a matter of fact, it shows that you're using it on the southern wall already. And it should also be on the other walls, but it's not shown in the image.