I doubt it will really go yaoi route, but I think the author will keep teasing us just the same. This is kinda similar to 07 ghost where it is really close to being yaoi (or perhaps shounen-ai, technically), but never quite crossed the line.
I am fine with this, as I am a big fan of the genre myself, but I hope it won’t drive other readers away, because I believe this manga has got potential even without the y-subtext (but it is even better with the subtext, well, at least for me lol)