Take your pick of currently available systems from Fujifilm, Sony, Olympus, Canon or Nikon. Loads of MILCs to choose from. Why wait for some mythical M3 that will prob never see a US or Europe release?
The current gear available today is more than good enough. The only limitation is the photographer.
I'm not waiting for the M3... I've got the M and happily use it. There are tradeoffs to every platform and contrary to popular opinion, there are key befits of the M that must be given up to move to the other platforms.
Fuji looks great... APS-C, great design... wait, is that a 23mm prime and 10-24 zoom for $1900? That's not a trade off... thats the price of a trade in car!
Olympus looks great... oh wait, another ultrawide zoom for 2 times what it cost me to bring in the 11-22 from another county? Great! Oh and superfast AF and 8fps on a $700 body... except the keeper rate sucks so forget that.
Will there be a M3? Hopefully yes. If it happens to bring in wifi, focus peaking and a handful of other electronic / processor based improvements that are currently available on the other platforms then there will be less to gain by moving away from the M.
What I absolutely do not expect to see are the micro 4/3 or Fuji platforms gaining the benefits of reasonably priced optics with a decent sized sensor.