You add days....
You just can't modify to remove all 7 original days.
You could add 10 months. As soon as you remove all 7 original days your whole reservation would be canceled and would not be back in the booking pool until 8 am the next day's if it was originally booked at 10-11 months.
What you are suggesting is that one must decide at 11 months the exact dates one must go and that they would lose flexibility of booking within a timeframe.
Why would anyone want to see that a change in dates must be a cancel and re-book. But, hey, like I said, someone like me with 825 points and 3 memberships, would have a huge advantage under your plan because I could secure multiple rooms, all at different reservations, for overlapping dares, for several weeks and drop them later. Not sure how this is any better.
Bottom line is as soon as you start saying changes are a cancel and rebook, you have completely changed the DVC product. And, that would hurt far more members who change trips outside the 11 month window that has nothing to do with walking.
I walked a reservation in March at my 7 month window because of airfare. I booked And then a few days later, prices came out. I adjusted it. Then I did more research and realized that if I switched airlines, I could go even cheaper. Modified again. Had to waitlist a few of the nights but Then walked and stalked, and guess what, over the course of a few weeks, switched the trip by two weeks, to get what I want.
We will agree to disagree that what you want to see to impact walking is something I say would be a big negative for the membership as a whole.