I make mine vague so they're easier to meet, and I let the CM know what I'm trying to accomplish and then they can help me better than if I give them some specific request. And always make sure the request is available within the room type.
Ex: in lake view room @ BLT I requested to be able to see the parks in the distance because it was my son's birthday and that would add some extra magic. There are a lot of lake view rooms like that. Some people will request "room ending in number xx" to get a room with the view they want, but that is just too specific. If they can't honor it, they put you somewhere random. But if you let them know what you're after, they can help you better.
At art of Animation I requested to not have a long walk to buses because my mom had a foot injury.
At por, we requested rooms that could see each other's door so my nieces could run back and forth between rooms and we could watch them all the way.
All of these requests were honored. We really don't go in "peak" times so that probably helps.