My suggestion is for more parts that have dual uses, similar to the "small gear bay" (the plane wheels). It would be nice to have parts like that, maybe retractable and extendable wings for example. I apologize if this has been brought up before, I did try to look for any other threads with this suggestion, but I didn't find anything. Edit: Also, I assume that gimbaling engines may also fall into the category of a "Mechanical" part.