Interesting topic, maybe I can add my muse...
I originally got the camera because I was interested in the small form factor that was also compatible with the flashes I used on my 5D. I wanted to check out mirrorless, why not when it was a steal and it leveraged the gear that I have (vs the impressive but expensive sony/Panasonic/Olympus variants).
Yup its slow, and the IQ is that of the 7D, the WORST IQ I've seen from a canon camera of that grade.
I also upgraded from an near zombiefied iphone 4 to an iphone 6 recently which made me reconsider it for snapshots.
so where does this leave my EOS usage...
The iphone is the camera that is always with me, thats both good and bad b/c as a photographer you usually had your camera at reach for those "moments"... and since it was the camera you had, it was a good one. Now I have a camera that I would have never bought as a camera (no zoom or interchangeable lenses, no RAW coupled with no real manual adjustments) attached to my phone which toggles my lazy gene to not have a "real" camera at hand.. so Pluses and minuses...
While I was hoping for the EOS to be a street camera, a 5D coupled with the 40mm pancake kinda fits the bill with MUCh better IQ and the response time of a fast DSLR AND a viewfinder... this really helps my composing....
that being said, My 'M goes on many trips b/c it fits in a small bag with TWO lenses, I can stuff my 600 speedlite in the bag, even the radio remote and have a compact camera system that is as versatile with flash photography as my 5D. When I go to family events where most folks would have whipped out an iphone and have a grainy photo, I end up with sharp image with flash filled or flash bounced images with WB and exposure precisely controlled.
This is my conclusion: I love the 'M because it allows me to shot that small form factor EXACTLY as I shoot the large form factor 5D. Its an albatross market failure of a camera.... doesn't meant its a bad camera, its just a bad consumer product.
ITs also gives me a peak into the small mirrorless form factor.
Here is my concern: with the M being an official crop sensor mirrorless camera (a great compromise), I'm sorry to say that, even with the 7DII, the sheer suck-a-tude of the current "crop" of crop sensors. I think canon traded mega pixels and a lot of software foolin' around for the fidelity for a natively less noisy image. I think it was the 40 or 50D that had and APS-C that was 10MP and 15 MP respectively that was the ceiling on IQ for the APS-C. So I think its a far chance that canon would release yet ANOTHER mount standard for mirroless for full frame. So we are stuck with the dynamic range challenged, grainy APS-C sensors for mirrorless.
Heres another thing too: since the flash isn't built in, and has to be external. why not make it more than just a "lifestyle" flash (read: underpowered).
here's what i propose for an EOS-M3:
Make it have a built in Radio for a new line of flashes that can either gelled quickly or have it have two bulbs (like the iphone flash) , one at 5600K the other at 2900K. they both shoot in tandem for the correct color temperature above indoor 2900... which makes sense since you will need more power likely.... built in radio offers off camera flash as STANDARD now. Imaging little go-pro style booms attached to these flashes so that you can throw light anywhere... Imagine the tiny little snoots and light modifiers that would fit these little thing.. I'd say no bigger than a 270EX with the bounce head feature too. "But won't the flashes be too small or underpowered" you say in your most annoying voice... Well imagine if the the EOS-M3 shaved off a few megapixels, say 12-15MP in leu of light sensitivity... so that i can live in ISO 6400, 12,800 easily without the sharpness loss. Marketing nightmare but a photographers dream.. whats the point of having a 18 or 21 MP image that sucks at low light and you end up losing resolution by noise reducing in post or in camera, right?
Smaller MP also means less DIGIC processing time, faster shutter, faster response, more pixels for phase shift whatever-the-funkity face stalking technology they have... it will be a better picture taking and overall IQ in the end. Every reviewer will pan it, but every canon user will buy it.
because you can shot with it EXACTLY as you do your DSLR AND its smaller AND you introduce some innovative technology: like built in radio for flashes, White balance smart flashes, bullet proof ad-hoc networking with mobile phones for instant uploading to the phone's camera roll, ready for sharing.....
What do you guys think...? besides that I went oFf topic, captain Obvious, What do you guys think would make a future EOS-M even a bigger keeper than the current one?