I think it can't hurt... I did it, although my requests were noted on the ressies as well. I do have to say, though... I was at the front desk when a family was checking in... and ALL of their requests hadn't been met... and they weren't happy! They wanted: a room on the highest floor possible, which, according to the CM at the BC is 4th unless you're concierge..., a full balcony - according to CM not possible on 4th floor (don't know if this was just that there weren't any available at the time, or if no 4th floor balconies are full)... and non smoking... I think they ended up with a 1st floor room.
I decided, when it was time to send my fax, what was MOST important to me... and sent just that request. My only requests were non smoking and a day bed... and I figured, since I was bringing my mother along (who is a smoker - but when we get a non smoking room, I send her elsewhere to smoke), that we could live with the smoking if we had to... but the daybed was most important since there were 3 generations in one room... and I refuse to share a bed with DD6 since she's a bed hog!
I guess, what I'm trying to say, just don't be TOO picky... and you shouldn't be disappointed!