The US999 price was cited in at least one review, not a price that I dreamt up. I certainly am not expecting the 12-35 to be cheap, but above a certain price point, it starts becoming too expensive to me. What matters to me is whether I think it can deliver the value for what it's worth. At $1700, I don't know abt you, but that's steep to me! The IQ wld have to be stellar to command that price. So yes it does depend on IQ, but can it live up to the price? Jury is still out.
I'm not sure what you mean by "better than micro four thirds quality". But my point is that there are other lenses in the m4/3 lineup that can deliver v good IQ that dont cost as much. Of course, there is no single lens that can match the specs of the 12-35 at the moment.
I haven't ruled out buying it yet. Waiting for more user reviews and pictures n of course, actual street price at our favorite shops.