Not able to answer all of your questions, because I'm not the one who came up with it and to others I cannot give you an answer, because I cannot give you information that has not been released in a product (i.e. if there are any in universe plans to take the design any further).
What I can tell you is, that the wheels are purely there for flavor. They have no extra rules and abilities (of course, you can always give them some in your game, your suggestions actually make sense from an engineering point of view). They look cool, they are something very different. For the time being, that is it and it is unlikely to change because that would mean, that we would have to go back and redo the stats for the Tortoise II BA, because it was constructed using the rules we have. That doesn't mean it will never happen (decisions like that are made above my pay grade and I'm not privy to everything that is going on in the Dev-team), but as it stands right now: nope.
Who came up with the idea ... no clue right now. But I agree with you, it is a great one. :)