Personally, I've already gotten used to the new controls and the hotbar. I think it's fine. The fly is pretty ok as well, the slow one is how old fly used to start and the fast is how it used to end. Quick presses of X can make things go by smoothly.
which is why i hate the fly, before the fly was the perfect speed for building.
Now with the new fly building anything will take 3-4 times as long, you are either way to slow, or uncontrollably fast.
the hot bar will be good after it gets its improvements, but until then there needs to be an option to remove it.