Pre-release, I was concerned about this, but now I've seen most of the companions that I am likely to see. Unless they introduce a new class, I am unlikely to level another one. Though I do have this wonky idea of leveling a character via PVP alone after the 1.3 legacy pvp xp comes in, but that is beside the point since companions are not used in PVP. I typically only raid and pvp, so I rarely even have my companions out anymore unless I am gathering resources. They can do what they want with companions.
Bottom line, I can live with it. New companions would be nice anyway. I'll just try my best to avoid the sexual story line. If it is as easy to avoid as it is with most companions, it won't be an issue. Though overt unprompted flirting could get annoying.
And likely to still be kicking around after
SGRA are in, in one form or another.
I would hope that it would go away after they are in. Of course, putting them in will probably just cause the people going on about this to want something more.