I like the trees - thinning them out, IMHO, would not be enhancing the view. Which may be why they don't do it - the trees make me feel like I'm in the wilderness - Bay Lake makes me feel like I'm at Disney World. I'm fondest of the resorts that take me somewhere other than Disney....its one of my favorite things about WL.
(I suspect the other part of that problem is that with trees on all sides of the resort, the lake and the parking lot are near equal in view. It is a LITTLE nicer to glimpse water through the trees. Thin out the trees and one view will be seen as superior to the other. Then you have issues at the front desk as people get demanding on which side of the resort they want to be on.)