But the big missing point is lenses, and how they will increase the size and weight of the larger format kit needed to realize most of the claimed advantages, if suitable lenses exist at all.
Look! The bottom line is this. The smaller format will always have the advantage of being lighter, but always at the cost of a sacrifice in image quality. If someone can design a smaller format that is significantly lighter than a larger, heavier format but offers equal (or close to equal) image quality at a similar price, then such a camera will have a huge competitive advantage in the market.
The D2X almost fell into that category. Image quality is almost on a par with the heavier 1Ds2 and the savings in weight (as well as price) can justify, for many, that slight loss in image quality and increased noise at high ISOs. That's fine. I'm all in favour of the consumer having a choice, but ultimately, with equal technological development amongst formats, comparing the latest with the latest, the larger format will always retain an inherent image quality advantage.
The issue therefore revolves around the size of the various trade-offs. Is the weight advantage significant but the image quality loss only marginal, or vice versa?
It seems to me, the Olympus 4/3rds format is really a competitor to the APS-C format. Affordable FF 35mm could well knock it out of the market, as Michael predicts.
You argument that lenses longer than 60mm have a sufficiently large image circle for a larger format, even though they might have been designed for a smaller format, is working against your main premise here. Again you are shooting yourself in the foot.
To make this clear, I'll give a concrete example. Let's say I'm mainly interesting in shooting wildlife and sporting events where the smaller format such as the 4/3rds and APS-C supposedly have an advantage. I consider 300mm to be my most used focal length and I look around for systems that support an excellent 300mm lens.
I'm impressed with the Zuiko 300/2.8 for the 4/3rds system, but I'm concerned that the FoV might be too narrow (effectively that of a 600mm lens on FF 35mm), however a 300mm lens is a 300mm lens. The size of the sensor cannot change that fact.
I consider the Canon 300/2.8, also a very fine lens, up there with the best that Canon produce, if not the
best. I'm torn between the Canon 1Ds2 with 300/2.8 prime lens, and the latest 8 megapixel Olympus 4/3rds with Zuiko 300/2.8 lens.
I compare the specs. What do I find? Lo and behold, the Zuiko 300/2.8 is actually heavier
than the Canon 300/2.8; 3.3KG as opposed to 2.55KG for the Canon. I don't know what the street prices for these 2 lenses are, but the RRP prices are about the same, with the Canon perhaps being marginally cheaper.
Now I'm not going to quibble about a few grams. A 1Ds2 plus 300/2.8 lens is going to be insignificantly heavier or lighter than an Olympus/Zuiko 300/2.8 combination and therefore not a factor in my deliberations.
The point has been made many times in this forum; it makes no difference if the camera's sensor does the cropping or the image editing program. Cropping is cropping.
The difference between these two systems is one of cropping choice. With the olympus/Zuiko 4/3rds system, I've got less choice. The sensor crops the image circle to a far greater degree than does the FF Canon/300mm combination. I would therefore much prefer to use the 1Ds2/300mm combination, unless, of course, the cropped 1Ds2 image is inferior to the Olympus 4/3rds image .
And here's the rub. I haven't seen any direct comparisons, but I'd be prepared to accept that currently the 8mp Olympus image would be sharper and more detailed than the cropped 4mp 1Ds2 image. If this wasn't the case, there'd really be no reason for the 4/3rds system to exist.
However, this latest article of Michael's is addressing trends and future scenarios. The current advantage of the 4/3rds format in my example above is partially offset by the choice of a wider FoV with the FF format, with any lens. Furthermore, the resolution advantage of the 4/3rds format will continue to be eroded as it becomes economically viable to produce FF sensors with higher pixel densities.