I think that what we will see with the L Mount 'Alliance' is nothing less than an assault on the pro orientated DSLR market dominated by Canon and Nikon. It strikes me that while Canon and Nikon have concentrated on competing with Sony, Leica already and now Panasonic are out to prove that mirrorless high end is the way to go and they are determined to eat into the diminishing high end DSLR market. I think the system as a whole will be big, heavy and expensive with the emphasis on top of the range high quality lenses. I don't see any 'kit' zooms with slow aperture settings appearing. Leica don't do that kind of thing anyway, the Sigma ART lenses don't compromise on size or weight and Panasonic would be ill advised to try and replicate m4/3. I think the point here is to make the whole system as robust as possible to show that mirrorless can handle everything a D5 or 1DX Mk II can. Neither Sony, Nikon or Canon have so far demonstrated any appetite to do that and the Leica SL (Typ 601) is the only attempt to do 'pro' FF Mirrorless so far. I think any resemblance to m4/3 will be only in the fact that the name LUMIX is on the front of the camera.