What I find interesting about this idea, in the context of brotherly love vs sexual or romantic love/activity is...assuming a director wanted to employ this idea as subtext in a production, how exactly would the actors play that? How would this subtext shift the playable action between the actors playing these two characters from a close, brotherly bond to something more?
I cannot think of any way that this could be played that wouldn't be too much or too wrong or not the authors' (Laurents' comments notwithstanding) intentions.
So...for practical purposes...what's the point? You could just as easily come up with any other subtext that makes it more interesting for you (Baby John is an alien from Mars/Rosalia is secretly from a wealthy family/Bernardo teaches ESL at the community center), but, if there's no way to actively play those things within the context of the material, none of it matters.