Interesting thread topic, thanks Peter.
I'm one of those guys who just doesn't care about size and weight - like, at all. If the system that fit my style was an 8x10 box camera with massive heavy bellows all which required one of those uber-bulky wooden tripods then I would find a way to strap it comfortably on my person, bike and into my car. It's not hard IMO.
Last summer I was mostly to be seen carrying around a Linhof tripod, a gimbal head, the GH1, and the Canon FD 300/2.8L with me just about everywhere I went. I learned to arrange it comfortably and it wasn't a problem ever after. Here's a pic of me next to just the Linhof without even the gimbal head:
For me I find most of the µ4/3 lens offerings to be lacking wither in character or in IQ as well as overpriced. That's just me and you don't have to accept my views as your own - lucky you. So for me I don't really benefit from the weight reduction realized when carrying a whole bunch of lenses around - because I'm almost always using alt MF glass. I'm also usually a one lens kinda guy and almost never have the desire to carry more than one - so that works out.
I think any decent digital camera of about 8 ot 10 megapixels can print to any size with no restrictions at all. The way our printers work we're good to any size we can print on printers which will fit into our homes. And larger than that printed commercially, is also doable because of the way viewing distances correlate with the human imaging system. If it looks good at 8 x 10 it will look good the size of the empire state building.
Contax 35mm film camera - FujiFilm 400
Nikon D700 (12 megapixels)
Nikon D700 (12 megapixels)
Closeup from the above shot.
-= Sorry to have to blur out some of the details for (C) agreements =-
So for me resolution is mostly only about being able to crop into an image more or less as the megapixels increase or decrease. Maybe some of you have noticed that at web-sized scales the D800 with it's 36mpx sensor doesn't look all that different from the D700 or the 5D's 12mpx ones given all other things being equal?
But I guess at the same time everyone notices quite a lot of difference between the D700 12mpx images and those of the 12mpx µ4/3 cameras? I do anyway. The OM-D closes that gap somewhat (over something like the GH1) with the amazing job Olympus did of synthesizing some of the missing dynamic range back in to the images but it's still not all the way there. There is just something about FF images that look more "professional" (if I can use that term in this way) and I think it has to do with a combination of factors not limited to just sensor size - although that's probably the biggest factor.
The way I see things mirrorless interchangeable lens cameras have really filled a niche being true to the concept of a "Bridge Camera". PJs may become brave enough to venture out alone with them as they are now and as they get better but for weddings, professional portraiture, and such I don't think they have what it takes. And even though I'm quite surprised by what Olympus did with the OM-D I don't see µ4/3 seriously entering those areas in the future. If all other conditions are perfect they can come close but how often does a professional photographer find him or her self in a situation where that's guaranteed to be the case? Even in a studio environment using µ4/3 in place of a FF or MFDB means that a lot of extra setup time is needed in order to compensate. This is likely true of post processing as well.
For any kind of professional action photography all mirrorless cameras fail the test. Their AF tracking abilities are just way WAY too weak. And while their AF is now pretty dang fast it's really not very accurate! Good enough for us hobby and street guys probably tho. Even some of the second tire DLSR models have difficulties in these areas. Professionals pay the bucks for models like the D4 and the 1Dx for a good reason. Here again I don't see µ4/3 approaching a professional's requirements or expectations anytime soon. In fulfilling the desires and requirements of a bridge camera user I sure do though!
So in looking at both the current state today as well as the future of, µ4/3 I think it's useful to define or have some idea of what a bridge camera's purpose is. Besides of course being "good enough" to allow users to enjoy the experience of photography, I think bridge cameras are true to their label in several ways but mainly training and progression.
Training is accomplished via the camera's feature set and the offered options that accompany the system. This is all encompassing from the basics such as aperture, shutter, and file handling to the more bell-and-whistle-ish features like intervalometers, off-camera flash control, and wireless connectivity. The more we're trained to incorporate such features in our fun and learning experiences the more we will want to upgrade to systems more robust in those abilities and also the more creative we can be slash fun we can have - hooking us into it so to speak. And there it goes... The more hooked we are the more time we spend doing it the more we want to maybe get it to pay for itself by going pro and/or the more we can justify spending more for more robust more convenient systems and system options.
Right? Check it. The more one uses an on-camera built-in flash as just one example, the better they get with it and the more ways they can find to both justify upgrading to and increasing the desire for, high grade flash guns and later maybe even studio strobes, soft boxes, reflectors and so on. I see these basic underlying principles in just about every aspect of µ4/3 cameras. John W's comments just above exemplify this "progression" perfectly IMO and I see it all the time here, at other sites, and in my conversations with other photographers in person.
So that's mostly what I see the state of µ4/3 as being today. A currently well fleshed system which bridges users from smaller systems, phones, or even no camera at all over to higher dollar more capable and robust systems as they become ready and/or wanting to do so. Like all of you I of course also see people using µ4/3 as a secondary and complimentary system to their larger DSLRs as well as those who have realized that they're not really into it enough to want or need to carry around a larger DSLR - though mostly the later are people who previously owned 3rd tire systems or APS-C DSLRs.
What I expect to see in the future from µ4/3 is in direct line with this model as well. More fun slash convenience features that make us get into it more and when we do then upgrade to systems that do those things better or faster enough to justify the purchase. Personally I'm among the ambitionless sorts who aren't going anywhere with it and don't really want to either. For us µ4/3 cameras and their feature roadmaps are very well suited.