For a thread about the survival of m4/3 I think there has been a lot of emphasis on the pocket rangefinder concept of m4/3 and not enough on the small system concept.
I am in the process of choosing my first digital system camera, with no legacy lens issues to consider (as I am not serious about using my Canon FD lenses with adapters).
I pursued the ultra quality approach (FF) and by the time I pack my fantasy desired kit of one body and an ultrawide zoom, 50 prime, 100 prime or macro, and 70-200/300 zoom plus a flash, the kit weighs about 3.5 to 4.0kg, even using f4 zooms.
I then examined APS-C and found the primes are basically FF units anyway and the zooms also tend to be FF unless I accept kit-zoom quality. The weight and size saving was not what I anticipated.
4/3 was close to APS-C, and hence close to FF! Although some lovely lenses on offer, but no size or weight saving worth bragging about.
m4/3 is completely different, offering a kit based on a GH1 that quite frankly blitzes the three above for size and weight while offering excellent quality and ranging from 14mm to 400mm (equivalent), and a total weight of 1300g as a travel kit is very compelling, as I have enough sore shoulder holiday memories from my SLR kit which is, discouragingly, lighter than any of the above 3 DSLR kits (although I am not saying it is equivalent to them, being 1 body 4 primes and a flash). With the above GH1-based m4/3 system, most body/lens combos weigh 500-750g vs 900-2200g for alternative systems with equivalent fields of view. The GH1 sensor matches the leading APS-C sensors (on average), and one could add one of the RF-like bodies for use as an everyday carry-to-work camera, doubling as a spare body or spouse camera on holiday. Hmm!
For the other makers to seriously compete on the above terms, they need to (a) make a new suite of lightweight compact lenses, and ( b ) release something that competes head-to-head (with no material IQ loss) with their own APS-C lines, which even now depend on FF lenses for much of their high quality range. Sony have started (a) but they have not embarked on ( b ), probably wisely, and Canikon may also be wise.