I think if Canon prices and specs the camera well enough this could be very interesting.
I can't really see the business case for a low end MF camera. Most "prosumers" would just find it too bulky, slow and expensive compared to a good FF DSLR for most of their photos. It was true in the days of film and it is still true. Moreover I wouldn't call a 5-7k camera a "prosumer" one, at the prices you can buy a 6D/5D MkIII and two/three very good lenses.
Moreover most LF users AFAIK prefer high quality primes to zooms. After all when working with the camera mostly on a tripod in a controlled environment framing can be done moving the camera and/or changing the lenses.
Also MF usually lack supertelephoto because they would be really big and heavy, while many lenses has a leaf shutter because of faster flash synch speed, especially when using studio flash lamps and not dedicated strobes.
If Canon really wish to enter this market it has to do with the right specs for the existing market, not try to create a new one that could never materialize.