I see the antique fellows are gathering around again... "lenses have to be cylindrical and metal only", haha.
I don't dislike the lens design, I just hate the super-poor quality of the lens hood and front-covers (for the Touit, that is, but it's the same or worse on Batis). Getting no firmware upgrade from Zeiss is another weakness.
Hood is rather alright as long as you don't mind the extra size. You can't reverse it though, is that what you hate about them?
Lens cap is... another story. How could they make it that bad?