OK. I see where you're going. Thanks for the clarificatiion.
As an aside; increased chromatic abberation would probably be due to poor correction in the additional lenses.
But to get back to your main premise --
Teleconverters existed mainly in the pre-zoom era as a means of keeping the photog's lens collection within reasonable bounds both physically and dollar-wise. Zooms made teleconverters far less useful, if not yet completely obsolete. I suspect that today folks use them only to keep from popping for really long-focus glass, which remains expensive.
Teleconverters do result in a degradation of the image, but it's mainly due to the low-cost construction of the optics in them. A modern high quality unit would be interesting to use. Trouble is, it would be expensive. A good zoom might actually be cheaper [economy of scale]and would probably have greater aperture.
The reverse of a teleconverter, as you describe it, would essentially work by reducing the effective fl of the main lens. Instead of a zoom working at an effective fl range of, say, 50 to 150, it would become a 33 to 100. While this would be theoretically possible, I don't see much of an advantage to doing it. Zooms for today's digitals come in a wide variety of surprisingly large ranges. Really wide wide angle lenses are available without having to mortgage the house.
There's one more point, and it's a real doozy; the position of the converter lens' rear element. Teleconverters decrease the angle of ray convergence. The 'stronger' they are, the farther from the film plane they must be positioned. No sweat. Makes the rig look cool! Kinda like a 'Hummer' effect. A reverse teleconverter, though, increases the convergence angle and will have to be positioned closer to the film plane. For a RF rig, this might work. However, in SLRs, there's the geometry of the front edge of the mirror's flip-up arc to take into account. Its clearance is usually close to minimal to begin with. I would suspect that a reverse teleconverter of any significant strength would result in an impossible geometry.