I think they've spent far too much money on the new TARDIS interior & opening title sequence to change them again now. I think they, and Clara, will at least be around through Season 8. Unless Clara somehow doesn't survive the next 2 specials at all.
And, personally, I'm not sure there will ever be a better time to do a female Doctor. I mean, there's been kind of a logical progression in personalities from Paul McGann through Matt Smith. But Smith took it about as far as you can take that. I think the 12th Doctor will be a radical departure in some dimension or another. Might as well test the gender change while you're at it.