If landscapes are your main priority, the 17 TS-E would deliver in spades. If you need the flexibility to take on a range of subjects, then the 16-35 f/2.8II will have it's rewards too. Make no mistake, this is a fine lens.
The 14mm f/2.8II has an awesome reputation, but of course is limited in the sort of subjects you can tackle with it. 14 mm is very wide and may leave you feeling a bit restricted as a general purpose ultrawide. It needs to be used with great care. Definitely rent before you buy. And don't be tempted by a 14 mm f/2.8 MkI...most of them were shockers and are best avoided.
The 17 TS-E can give you a 10mm equivalent spread if you don't mind stitching you landscapes. On a good tripod, just using the lateral shift, you do one exposure in the centre, shift left and shoot, shift right and shoot and you'll have three frames that will stitch perfectly. The 17 TS-E is the landscape shooters new best friend. There is plenty to read if you're willing to search.