How do I make a room request for a view of crescent lake?
Speak to your
travel agent, or call 1-407-WDISNEY, and have then pull up your reservation. Ask them to add "Unobstructed View of Crescent Lake, please" to your reservation.
I know what you mean.

When we stayed at the Grand Floridian the CM decided to find us a room with a better view. We didn't ask her to do it. I often wonder what happened to the guests who were supposed to get our "new" room.
Once, at BC, we'd booked a SV, and about a week out, it changed on
MDE to "Lagoon View," needless to say, we were overjoyed! When we got there, the lovely CM verified that yes, we'd been upgraded, and asked if she could make our stay more magical with a king bed. We thought we'd hit the lottery, until we found out that the king room was a full-on rooftop SV! We rushed back to the desk, and had to really fight to get the original room back, because MDE proceeded to show us as SV, and the (new) CM literally didn't believe us.

There's more to the story than this, but that was the basic jist.
Also, on our most recent trip, we had a GV, and the room we were assigned was ready, but had a small balcony. I asked our check-in CM if there was another GV room with a full balcony available, and she said there was, but it was a few hours away from being ready. We agreed to wait and another CM with a clipboard kept approaching us trying to get us to take the original room saying she didn't know why we wanted to wait. It was really frustrating.
So, what I guess I'm trying to say is I think it's absolutely a possibility that the room you end up with, might have been the room assigned to someone else.