I have a beautiful Leica MD-2 that has no rangefinder or viewfinder - so, your statement that the anticipated M camera is the first M Leica without a rangefinder is not factual. The MD-2 is not the only model without viewfinder or rangefinder. I have it dedicated for street photography and use 15mm and 24mm Voigtländer non-coupled lenses with shoe mounted finders - oh yeah, also an Elmarit-M 28mm. It is like silk and silent.
The Leica M11-V is expected to be the first Leica M without a rangefinder, as Leica plans to install a high-resolution electronic viewfinder instead. This could significantly reduce both the price and maintenance requirements.