We love the BC and over the years we have always requested both a daybed and a full balcony. I spent a lot of time trying to figure out how many room configurations have both daybed and full balcony, and it's nearly impossible to know for sure. I've always thought (for CL rooms) that standard has a better chance of both requests, garden not as much of a chance, and I'm not sure about water which is the one you're asking about (though I don't think you're asking about CL rooms, sorry!).
As my kids are getting older now, we've conceded to the fact that a daybed is simply a necessity so I leave that as my one and only request. One time when I requested both, we got just the full balcony and no daybed, so I inquired about switching rooms and they gave us a cot because they said there were no more rooms available. We fit the cot in our room but it took up the space we needed to go out on our full balcony, so in the end we couldn't use our balcony anyway!