There's a balance between image quality and gear load/complexity, and people have varying thresholds of what is too heavy vs what is a satisfactory image.
On international trips, I invariably bring the M9 + 21/35/50, and at least one digital compact, preferably with a zoom and decent video. In the past, that second camera has been an Olympus E-M5, a Panasonic LX7, or a Panasonic GM1 with a few primes and the tiny kit zoom. Now, it is likely to be the Panasonic LX10, although the GM1 is small enough to sit in the corner of a bag and not be too noticeable, and it has better image quality than the LX10.
My most enjoyable photographic experiences have been with the M9, and secondarily with a high quality compact like the Ricoh GR, Sigma DP1, or the Canon S70 in the old days. There's something about having a small zoom camera that removes all the fuss about changing lenses and switching things around.
A m43 camera with decent fast primes is surprisingly good, even compared with the M9. What makes it even better is that the same sensor that is in the Panasonic GH3/4 is also in the tiny Panasonic GM1. It's good enough for a lot of things, and would make a great combination with the LX10.
For the best image quality, though, I'd go with the M9. For video, there's always a decent smartphone or even an action cam. The LX10 does really good video as well.
Raid, your last trip (?) was with two Olympus m43 cameras and you found that quite good. I'm working up the courage to use m43 as my largest camera for my next trip.
