BC:
We just returned from a great Dolphin vacation so I'll try to help. This is what I did for my room request: I had booked just a standard room for an 8-day stay.....gov't rate. Two weeks prior to arrival date, I went onto the Dolphin website and clicked on "Reservations". From there, there is a link for "Special room requests". I explained what kind of room I wanted, the view I was looking for, etc., and sent it along. On the day of check-in, the CM made no mention of any of my room requests, so when I handed her my Starwood Preferred card to be sure she credited the stay to my account, I asked her if there were any possibility of an upgrade (I did not have any points). She looked in her computer and said she found a room with a "great view", but didn't specify. Well, the pixie dust was flying because she gave us a room on the 8th floor in the East Wing....directly facing BC/YC and Spaceship Earth!! We watched IllumiNations from our room 3 times! This was a complimentary upgrade...we didn't pay anything extra for the room.
I would certainly send the email to the hotel AND ask at check-in. If you don't have one, the Starwood Preferred Card doesn't hurt either.
Good luck and I'd be happy to answer any other Dolphin questions for you!
Sammy