Most of the Zeiss glass (if not all) is incredibly good, and I'm sure that having a native mount can be good sometimes. In sure that there'll be lenses released in FE-mount that'll drop jaws.
On another similar note, what Leica glass do you have? I'm always intrigued by others gear.
my friend has an early 60s voigtlander that he never uses because "film is dead as has no place in modern photography"...
You are right about native lenses. My only problem with native lenses for mirror less cameras is that they have no helicoids or manual aperture control, thus no macro, no tubes, no extenders. I'm a free-lens lover and that is impossible through native lenses.
Back to Leica, I have the following:
Canon LTM 35/2
Leica Elmarit 28/2,8 ASPH
Zeiss 35/2 Biogon
Zeiss 35/2,8 Biogon C (What?)
Voightlander Ultra Wide-Heliar 12/5,6
Leica Summicron 50/2 (from the 80's)
Leica Tele Elmarit-M 90/2,8 (thin)
Nikon 10,5/2,5 LTM
The best of the bunch are the Summicron, the Canon, the Elmarit 28, the 35/2 Biogon, and the Nikon. But I'm pairing down to all e39 lenses as I like small and same filters. I think the only non-e39 lenses I will keep are the Nikkon and the Voigt.
I
wrote a lot about the bokeh of the Canon 35/2 LTM at ohm. It is a wonderful drawing lens, but has pretty poor mechanics. That is fine; the mechanics have stood up for years. They just aren't tip top. But the draw of that lens.... especially on crop bodies is incredible. On FF, it is a wide angle and so you get less of that smooth, circular bokeh, but it still ends up being beautiful.