I don't think that it's easier to design or make a camera with base tilt as compared to axial tilt. But I fully agree that it makes the camera somewhat more stable. Also, don't deminish the prevention of yaw. When a shot becomes complicated with both front and back tilts and swings, the presence of yaw can make the shot unmanagable. The intention with tilts and swings is IMO first to get everything sharp without having to resort to f/90 or so. It's equally important to also manage perspective while doing this. If the camera is not designed to prevent yaw from appearing, it's easy to get lost which results in lost quality, i.e. using smaller aperture openings than needed. This results in need for more light (maybe 4 times the flash output in a studio or several seconds exposure instead of one) and refraction effects on the film etc.
I think Sinar was the forerunner of building yaw-free cameras and their articles and camera manuals describes the problems and solutions quite well, using mock-ups with cameras and different scenes. Of course they promotes their own products, but without a lot of hype. They compare "before and after" with the Norma and the F/P series cameras, all cameras with very good reputation. I have tried to read other articles on Sheimpflug etc. but they are all very technical/theoretical and very easy to put aside.
//Björn