I have several hopes for such a lens:
- Optics near perfection (diffraction limited, little CA)
- Designed with 1.4x TC III in mind
- Terrific IS with no optical changes as lens elements move
- Under $2,000 street within a year.
- 77mm filter threads
- Fully removable tripod collar (preferably the same one as the 70-200/2.8 IS II)
I like this and think most are possible. Not sure about the 77mm thread. And no way on the collar, no money to be had by having a collar that goes on another popular lens model.