Good luck with this! It's extremely liberating to be able to use a smaller camera/system instead of a dSLR.
As others have said, the bottom line is often the "feel", the ergonomics, whether the camera is part of you (or vice versa). There is probably no one correct answer. To paraphrase some of Thom Hogan's recent pieces, the sensor and other technicalities are fast becoming less important in differentiating camera bodies, so just go with what feels right.
I recently did a 10 week human-powered ski tour in Norway and was VERY impressed with the Panasonic GX7. Originally I was looking for a new high end point and shoot, and almost in spite of myself got an interchangeable system instead. It worked far better for me than my previous small camera, the Canon G1X (which has good image quality, but I never enjoyed its ergonomics or the tiny viewfinder), and the GX7's EVF was a joy to use. If you ever plan on using a camera in snow or other bright light avoid anything lacking a decent viewfinder. My feeling is that EVFs are now good enough, and will soon eclipse OVFs. LCD screens are next to useless if you are in the snow or other bright light, and I am surprised more people don't grumble about them. Not to mention the shakiness of holding the camera away from your body, and the fact that if you wear glasses for reading an LCD screen is hard to read.
One of the big things in favour of any m43 system is that if you buy good lenses now, you can upgrade your m43 body in the future but still use the lenses. Some of the non-m43 systems appear not to have a good range of lenses so you might be forced into using legacy glass with adaptors, which it seems can be less than optimal (though I have no personal experience here). The only obvious gap I can see in m43 lenses now is the need for a quality wide angle prime.
Having said that, when skiing (or bushwalking, an Australian word for hiking) I want versatility with low weight, so I usually limit myself to a wide zoom and a standard zoom- the quality is quite good, but not as good as if I'd used primes. Always compromises!
One more thing- if you're looking to customise buttons, the GX7 has lots of scope for that.