Thanks, Ming Thein, for your thoughts and guidance in the blog. I sold my Nikon cameras a year ago, and bought new m4/3. Yes, there are compromises, but one of those compromises is my back and wrists. Olympus Pro zooms weigh half of what my Nikon lenses did, and are at least as good. Primes are a treat. Which they need to be to offset the noisier files from m4/3. ;-) I don't have super demanding corporate clients, but haven't had any complaints about size or quality of files. An E-M10 with a short prime can travel with me all the time. Add a 2# tripod and a bottle of water, and I can comfortably hike into the desert for last light photos.
I'm going with Yoda on this one, "Do or do not, there is not try." I carry what I think I will need, and people have gotten used to the bag I carry, and are always pleased with the results. And as you say Ming, why bother carrying something when the images it produces won't satisfy you if you get the opportunity.
I've found that I can't compromise anymore. I'll consider the iPhone great for location scouting (even then I'd prefer a proper camera), but I'd rather not have regrets for relying on it out of convenience. At all times I have either my Canon AE-1 Program with a 50/1.8 or the E-M5 with one prime or Pro lens. I like to travel light, but I've carried both on occasion space permitting. With regard to attending family events/being expected to shoot for free, I simply decided to draw a clear line. If there's a hired photographer present, as a courtesy, I'll shoot minimally or not at all simply because it will be obvious that I'm looking to capture something beyond a snapshot; inevitably, we'd just get in each other's way.
The Fuji Xtrans sensor produces very good images. The XPro-1 with 35mm f1.4 (52mm full frame equivalent) is a fantastic combination and gives you a rangefinder-like optical viewfinder. Smaller and significantly lighter than a Leica M, but not pocketable The XT-10 is also very capable and even smaller. Fuji has promised a 50mm equivalent pancake lens f2.0. The X100T has a 23mm (35mm equivalent) fixed lens, but with the high-quality Fuji teleconverter, becomes a 50mm equivalent and gives you a leaf shutter (flash sync at any speed).
The Leica D-Lux 109 (and the Panasonic equivalent) looks very promising. Micro4/3s sensor, native cinematic size support (not just a crop) and a fast lens. I have only used the Dlux 4, which is excellent, but I believe this is a worthy upgrade with a faster lens, bigger sensor, etc.
These options are not as big as the 645, but the image quality is capable of large prints. The lenses are outstanding on the Fujis (and I would guess also on Leica, but haven't used it). All of these cameras are significantly more discrete than an SLR and lighter to carry.
A good photo does not neccesarily be a high definition photo. Even with a phone, great photographs can be taken. I understand your ultraprint-inclined tastes but I think it is good for you (and for everybody else) to try to make good photos with humble equipment.
It is somehow like listening to music: you shouldn't need high cost hifi amps and speakers to enjoy it...
I carry micro-four-thirds camera. I don't consider it a compromise and images print very well up to 22". If I'm going out, I'll usually stick a pancake or quick prime on it.
Frankly, for these exact situations I feel that carrying my Leica ME (much prefer to the M which I sold because of weight) solves most of the dilemma - I feel I will bring back high grade material while people around me accept it with no fuss or wrong judgement. Full frame, 50mm Summilux, non pro look.