I can't speak to a comparison between the 16-35L II and the MkI or 17-35L, but the 16-35L II is a decent lens. Not stellar, but it gets the job done.
Having said that, I've been using it for panoramas lately, and I'm considering the 14L II (and/or TS-E 17L).
Knowing your penchant for quality (your single handed purchasing of and recommendations to RRS have kept them in business ) I'd strongly suggest the 14 is a comparative POS and the 17 is sublime. The only application I'd think of using the 14 is in action sports where the AF does play a good part, for stitching and landscape work the 17 is in a league all its own.
Yeah, I suspect you're right. If I'm going to get the TS-E 17L, I'll likely wait until after the rebate ends - I hate the mail-in thing, and the final price likely wont change post-rebate.