Interesting points. I handled a ZI a long time ago when I was less familiar with rangefinders, side by side with an M6, but ultimately Leica had the stronger tug. I remember it certainly feeling more "fragile" in comparison, but from what I've gathered this is mainly due to material choices.
In regards to this, did the battery simply not function below a certain temperature (as is common with depleted batteries), or did the meter turn on but the shutter would not fire?
Which also sparked a curiosity in regards to the electronically tripped shutter, presumably a copal. Are the reports of shutter failure at all on the ZIs?