There are some rather wide gaps in MFT lineup, though. Mainly a fast AF/IS portrait prime is missing, as are high-quality wide angle primes. If one is ok with slow or slowish zooms of varying quality, MFT is great, but good quality lenses with high IQ, AF and/or IS are few. There are some very promising rumors and it should get better as you said - and just today it did.
You can get a fairly wide range (7-300) of good, if somewhat slow, MFT lenses. As a former film guy, that doesn't affect me much, because I'm perfectly happy shooting 800 or 1600 with a MFT and the slower lenses. There's also the Voightlander 0.95 25mm in a native MFT mount, which Michael likes, and now the new "Leica" 25mm. I was a bit disappointed that this Leica was a 25mm, although I guess it makes some sense, to come out with a fast "normal." But I think a 45mm fast portrait lens would have been preferable. And I think it will come.
But no matter, because the main thing about MFT is size. Frankly, I don't think the NEX and MFT are direct competitors -- rather, the NEX is competing against other APS-C cameras because of the size of its lenses. The key to MFT is simply size, nothing more. The four-thirds concept was dying before MFT came along, because nobody could think of a good reason for it. The cameras were essentially as large as APS-C cameras, but the sensor was smaller, and slightly less capable, in comparable generations. The whole game changed with MFT -- both the cameras and the lenses are sharply smaller, and yet, the quality is good enough even for most commercial purposes. (Though if I were going to be a commercial photographer, I would not choose MFT, or APS-C, I'd go full-frame or larger.)
The problem with NEX is that the lenses can't shrink much. It's like the reverse of the problem that the full-sized four-thirds had. What's the point of a tiny body if the lenses can't shrink? You still wind up with a bulky system. Sure, you save some weight with the small bodies, but you also lose function available in larger bodies (like the mirrors -- EVF may someday rival the quality of a good mirror, but it won't be soon.) If you're going to have big lenses anyway, you might as well go with slightly larger bodies: the Pentax K5, for example, which uses the same sensor as the new NEX, is a pretty small camera, with a really fine optical viewfinder.
MFT loses a bit of quality to the APS-C sensors, but not much -- probably undetectable by most people in most common print sizes. What it has is, the very small lenses to go with the compact bodies. I can carry a wide range of lenses and three MFT bodies in a Leica pack meant for two bodies; I can carry an GF1 with either of two pancakes, attached,in a jacket pocket, and a nice zoom in the other jacket pocket, and have a pretty good system with me. Can't do that with NEX. Can't even do it with a Leica.
I would jump to NEX in one minute if they could figure out a way to shrink the lenses. I don't necessarily need the extra IQ, but I'd like it, if I could keep the system small. I don't think they will be able (or willing) to do that. The biggest benefit and the thing that would really make the smallness of the NEX more viable would be four or five good pancake primes (look at Pentax as a model.)
Anyway, I think arguing about IQ between NEX and MFT is a little goofy - not only is there not much difference, IQ is not the reason people will go to one of these systems. It's size, and not just body size, but in-the-hand size. In the purse size. Long-distance-travel size.