As an EOS M owner, an EF-M prime or two would be welcome. EF-M primes with proper markings would be the bees knees, but I ain't holding my breath. The 22 kit lens produces a very nice image, albeit, the AF can be problematic, there is no question there. Right now, I mainly to use m39 or m-mount lenses with an adapter for their size and that they're easy to focus...the screen on the EOS M is very, very nice.
Now and then, I lament not going the Fuji route but really, only for the X-Trans sensor (or just going a little nuts and buying the Sigma DP 2 Merrill). I shoot enough video that I wanted complete manual control over it, someting the Fuji does not offer, which is even more of a head-scratcher, for me, than any shortcoming on the EOS M.
The bottom line, for me, is that while it's an easy target, the EOS M is a fun camera with great IQ. Whenever I think of it's shortcomings, I just have to look at the pictures it produces to clear those thoughts.