I haven't purchased this lens since I am not interested in this FL, but, when Zeiss releases the Otus 21 or 25mm, I'll be all over it if it stacks up to the 55.
From the perspective of someone who is interested in the Otus concept but doesn't have the personal experience with one yet (and I'll defer to those who actually own one), the main draw to the product is its sharpness across the frame @f1.4. I see no reason why an Otus (assuming identical optical goals for all future FLs in this series) can't be used at f1.4 on a landscape with infinity distance across the frame and get acceptably sharp corners (judging from samples distributed by Zeiss). Even if one had to stop all the way down to f2
, this will keep diffraction well at bay.
OTOH, @f5.6, if one wants to save $1k, an A7r with an FE 55mm ($3k), appears sharper than the Otus/D800 according to a comparison tool over at DPR (I think they got the raw numbers from DxO).