Just another quality of life suggestion. Maybe adding some configurable shortcuts for rotating a block while in build mode? Would function basically the same as before, but now you wouldn't be holding the advanced build mode button and moving your cursor to the small left/right arrows.
For example, choose block with mouse wheel/toolbar, highlight where you want to place it, and than hit c or v to cycle forward/backward through rotations, and than click to place.
For example, choose block with mouse wheel/toolbar, highlight where you want to place it, and than hit c or v to cycle forward/backward through rotations, and than click to place.