MWP,
Has anyone switch from N17-35 to ZE 21 + ZE 35/2 combo,
Sounds like that age old winless debate of prime IQ vs. zoom convenience - I have both - and the C/Y 21 prime is probably my most unused lens - love the IQ but inconvenienced by the wide fixed 21mm FL and too large and heavy to carry around "just in case". I use a C/Y 35-70 for my 35mm landscape prime - very, very close to the IQ of the Z* 35mm prime - but has the convenience of a zoom with those cool C/Y colors. I find 24-28mm a more useful FL than 21mm.
I've been meaning to do a test of the 17-35 vs the 21 prime - although the 17-35 is very strong at 21mm I'm sure the prime would edge it out for overall IQ but not by much. I did do a test of the 17-35 vs the C/Y 35-70 @ 35mm - stopped down you could not tell a difference using a 5d.