If we ever see a wide angle lens to match the 45/1.8 or 75/1.8 in sharpness, even stopped down, I'll be very happy. The sensor may be fine, but the available wide glass is awful in comparison.
--Matt
(And if you know of a wide lens I've missed, please tell me!)
This is an interesting question. If you don't need to go wider than 24mm eqv., the Zuiko 12mm is very good. The Panasonic 7-14mm is very acceptable and better than most zoom lenses within its range, but it's heavily software corrected. I expect the Zuiko 7-14mm to be much better (and larger, heavier and more expensive too).
Some of the really great glass for m4/3 are actually some of the "old" 4/3 lenses. I use the PanaLeica 14-50mm f/2.8-3.5 a lot, and it's flawless at any focal length, any aperture. It's slow focusing on anything other than an E-M1, but so far, I have lived comfortably with that. The E-M1 is on the shopping list. An absolutely stellar WA lens is obviously the Zuiko 7-14mm for 4/3. It's a large lens too, and not cheap, but it's really, really state-of-the-art.