Don, just to mention it: If you're into moving subjects, the Z 6 II is the better choice.
I can't really say how people coming from other brands will find the Z 6, though. I've owned Nikon cameras since the late 1980s - for me, the Z line feels like a natural progression (and yes, an improvement on almost all fronts). But people who have owned other mirrorless cameras might feel differently. YMMV!
And as for the size thing, yes, that's definitely true - but that's where the Z 50 comes in and does a much better job than I ever hoped it would. Did I mention that the files coming from the Z 50 comfortably match or beat those coming from the Sony A7 II at higher ISOs?
For the record: At the moment, all other systems I currently own (with the notable exception of the M mount) are on the line - however, I don't think I'll find anything that can fully replace my
gear any time soon, especially the Olympus E-M5 III, and also the small, fast primes and wonderfully compact, weather-sealed zooms. And even though I prefer the shooting experience of the Fujifilm X-E3 over that of the Panasonic GX9, the latter isn't a worse camera - in many respects, the opposite is true.
So, my Sony and Fuji stuff, as much as I like some of it in some ways, is practically on its way out (with Sony leading the way). The Z 40mm and Z 28mm will replace the Sigma 45mm f/2.8 and Samyang 35mm f/2.8 (and make the Sony A7 II and the A6000 redundant - finally), the Z 28mm can also replace the Fujifilm 27mm ... Yes, the Z 50 with the 28mm will be bigger than the Fujifilm X-E3 with the 27mm, but not decisively so. For everything else, I'm already well served by what's available, especially if I keep
: The one lens I can't seem to see anything on the horizon to replace it with in Z land is the Fujifilm 23mm f/2 - but then, the Panasonic 15mm f/1.7 pretty much matches that lens's output and is the more consistent performer (the 23mm is really pretty weak at close range, the 15mm is solid).
I didn't mention it here (much), but I've done shootouts with many of the lenses and bodies I own over the last couple of weeks to see which of my secondary systems delivered what Nikon couldn't and
wouldn't; what you've just read is kind of a summary: Only some small primes seem to be hard to replace at the moment; specifically, the Nikon Z lenses match or beat their Fujifilm counterparts in all respects but size.
M.