WARNING - long post with lots of info.
Basically my photography hobby has dropped off due to a bad shoulder and being unable to lug my gear around for longer than half hour any more. Before someone suggests waist pack systems, I tried and hated it.
Current system :
40d with canon 17-55 2.8 handles 85% of all shooting
40d with canon 70-300 or sigma 10-20
I have several other lens too that I only use once in a while. Sigma 105 macro, Tokina fisheye, tubes, etc....
My shooting is normally :
Travel photos -Look Big Ben (click). Look Grand Canyon (click). Etc
Low light photos in night clubs, street parades after dark, inside house,etc
My puppies
I used to do work for local magazines, sponsors, and creating product shoots from studio set ups. (Which I can still use my current DSLR for if I do it again). I don't shoot sports or blow up prints. I don't use my camera for video.
Basically I don't want to lug a system that weighs a lot around but really don't want to give up the nice IQ that my current system delivers even on "fun and silly" shots.
Would an M43 system deliver enough to meet my expectations? Does it focus as fast as my canon system does? If so, which body and lens for the M43 would be best suited for my shooting style that relies mainly on the 17-55 2.8 FL.? I would like a decent wide angle lens and telephoto lens to use at times too.
Many thanks for reading and taking time to reply to my question. Sorry for bad typing and typos as I am using my mobile for this posting.

