Actually, you miss quite a bit of scenery, as from Seattle,
DCL will sail out in the ocean, west around Vancouver Island to get to the Inside Passage. You miss a lot of gorgeous scenery that you would see if you were sailing from Vancouver and going between Vancouver island (and the other islands) and the coast of Canada. Plus, the seas in the open ocean from Seattle are generally much rougher than the seas between the islands.
No they won't. If you look at the itinerary map, they sail West of Vancouver Island, and don't enter the Inside Passage until what looks like somewhere near Port Alexander, way north of Ketchikan. They'll sail the inside passage going from Tracy Arm to Juneau, Skagway and Ketchikan, but then are back out in the ocean sailing to Victoria (which they will approach from the west and around the Southern end of Vancouver Island). So they will miss a LOT of scenery on the first & last days. And when they *do* sail the Puget sound back to Seattle, it will be in the middle of the night.
If DCL were taking the route you described (which they are when leaving from Vancouver this year) then it *would* be lovely. But they are not.
See above. Also, they are spending less time in Ketchikan (7:15 am to 12:30pm) so that they can get to Victoria at the end of the last sea day & spend only three evening hours (7:30pm to 10:30pm) there (to satisfy the foreign port requirement, since they are not coming or going from Vancouver).
It does make getting to and from the cruise much simpler, and Seattle *is* a lovely city, but, in my opinion, it is a far inferior itinerary compared to this year's.
Sayhello