The M8 cool in that it gives the user either option; handgrip or no handgrip. Many cameras don't offer that.
As for me, I had an M8 and didn't care for the handgrip.
Instead, I pulled off the slick covering and put a Griptac cover on it. Much nicer.
With regards to a Leica µ4/3, I don't see anything viable, either. Anything with the build quality of the M8 is going to be pricey but won't really offer any better imaging, and the technology moves too fast to invest in such build quality.
The camera body is just a computer with a lens mount. The technology in the bodies moves at such a rapid pace. Leica is too small, too slow, too methodical to keep up.
Instead, they should expand their lens line...along the lines of the 25/1.4 they make in 4/3 mount. For comparison, the M Leica 24/1.4 is $6000, the 4/3 Leica 25/1.4 is $800 (B&H prices.)