I've read lots of threads re: this issue and was under the impression that requests when making the reservation ahead of time took precedence. WELL, we recently returned from our first trip home to BCV (an addon; we also own BWV). The reservation was made exactly 11 months in advance with requests of top floor, Epcot view. When we checked in we were assigned to a 3rd floor room overlooking the valet area in front of Beach Club hotel!! What a disappointment. To top it all off, it was one of the 1 BR's that doesn't have a balcony off the master. The CM at the desk was not very helpful, the best they could do was move us to a pool view. Not the best experience my first time home.
Now in contrast, we also moved over to the Poly for the last 3 nights of this trip (used our free nights from when we purchased the addon). My husband faxed the room controller there prior to leaving MA and we got exactly the building, floor, and general location we requested! At least we ended on a high note!