Well, I think most WoT readers agree that there were a good 3 books there which were a slog, so removing those makes it 11 seasons already. Remove some more of the non-core sub-plots and characters, and I can see it as a GoT-like 8 seasons.
Any less than that, and we're talking about significant omissions in the show, and that would probably not work well (for book fans, at least).
Some things hinted at a major character won’t be introduced right away. They couldn’t film all the crazy amount of locations in the book. Some things had to be condensed for the show leaving them with difficult choices resulting in some changes. Rafe is trying to keep the TV show as close to the book as possible and they consult with Sanderson and others.