Well, that's an alignment issue - Basements as they were in CR would actually neither hinder nor help you in that task. Admittedly, they would stabilize your setup after you made sure that the alignment was proper. But note that without basements you are actually more flexible in that you can simply dig away a bit of ground below buildings in order to restore alignment in whatever situation you find yourself in.

Edit: But just to make that clear, I still agree that it's probably the best course of action to give the elevator a basement. After all, it needs all sorts of special cases anyway due to the hole in it. Just whoever does it should be aware that the width we now use for the elevator basement will probably have to be the (minimum) width of the standard castle segment later on in case we want to be able to cleanly extend this towards castle elevators.