This is a recent shot with the MC 35/1.4, perspective/distortion uncorrected, focus on the door:
This is an older one that I shot for testing distortion and that convinced me that the lens is a keeper:
Yes, one can see slight distortion in some situations, but there are so many lenses where distortion is similar or worse, and nobody cares .... Including, for instance, the 35/1.2, or the new 28 Perar, the Leica lenses mentioned above, etc. BTW, even the 35/1.4 Asph has distortion of similar magnitude (I've only tried v1).
Did you ever compare to your Nikon F mount lenses, including 35/2 and 35/1.4 ? Now there are some heavily distorting lenses .... (I have the 35/2).
For some reason the 35/1.4 Nokton is the only one where slight distortion seems to matter on the intertubes ... "Internet Rufmord" if you ask me
And don't get me started on "Focus Shift" or "softness". Whoever complains about this should first get an RF collimation on his/her Leica, then we can talk. Yes, the 35/1.4 is soft in the corners wide open, but so is my pre-asph Summicron, stop for stop, they are so comparable, that you cann't distinguish them even when pixel peeping.
And nothing against the pre-asph 35 Summilux in your hands, it seems to work for you. For me, however, it would be unusable in most situations at f1.4 due to "glow", I much rather have a slightly distorting lens that I can correct for in photoshop, but that focuses down to 0.7m without prominent veiling flare.
And just for fun, another recent 1.4 Nokton beach shot (I've shown this before)
And an older Bokeh shot (with worst case background):
Try that with the pre-asph Summilux, and there will be coma "butterflies" all over the place.
The 1.4 Nokton is very, very good for my purposes. And it's not really a matter of price for me.
People call the Nokton "affordable", but IMO, a US 500 lens is not
cheap for most any photographer out there, except for the very few people who are used to the insane current Leica lens prices.
The 35/1.4 Nokton for me is the perfect partner to "Big Bertha", in particular wrt bokeh and distortion. Sometimes, when I use M3 only, I pair Bertha with the 40/1.4. Where I consider the 35/1.4 good, the 40/1.4 is outstanding, very sharp and rectilinear.