Upload & Sell: On
Late to the party ... but since getting my 24L TS-E II I essentially quit shooting my 21mm or 20mm glass, the jump just isn't enough in most instances to even bother switching lenses ...
I bought my ZE 21 on the same order/shippment from B&H as my 24 TS-E II. An expensive order to be sure!
So for me, poetically speaking, they were born on the same day, as twins, with only hopes and no particular advantage one over the other.
In less than a year, I'd come to the same conclusion as you Rusty, there wasn't enough FOV difference between them. The slightly wider 21 lost its angle by cropping and straightening, whereas the 24 retained its "angle of integrity" through shifting. I also preferred the zero distortion of the TS lens compared to the ZE's moustache, that again needed cropping. If anything, the TS was sharper from edge to edge, and definitely had considerable less light fall-off/vignetting that the Zeiss.
All these factors, and a few less significant, made the choice to get rid of the ZE 21 relatively painless. But not completely without sense of loss or discouragement. Like a brilliant child who never grows into their potential and the dreams you surround them with.
I miss the focal length for its possibilities, and wish I had a 20mm Shift-E that took filters -- that would be awesome! In lieu of that, the 24 TS-E works beautifully for me.