As a prime lens user (mainly 35, 85, 20 in that order), the 20-50 f4 L is the first zoom lens to interest me in years.
It would be equally small, and cover 20, 24, 28, 35,50 and with crop factor, ~80. I.e. 99% of my photography in one lens, that potentially doesnt extend crudely at your subject like most other standard zooms.
A 35mm with crop covers 35 and 50 at f1.4/f2 so that would still likely be on my camera most of the time, but the 20-50 might get a lot of use and be perfect for travel and casual shots.
Would be great if you could have a subtle click feedback at e.g. 35mm. Leica used to have a lens with three set focal lengths i.e. not continuous. But if it doesnt extend when zooming, it can be left in position anyway without needing to ...