I actually rather doubt Tennant will leave. I mean, if the BBC was so eager to keep him that they were willing to do specials while he does Hamlet, I don't think they'll let him go so easily. And David still seems to love this job, so I'm not sure he'd want to leave.

I do sorta want him to, though. First because I don't want Moffat to potentially mess up Ten's character, and second, because I think the specials would be a good place to wrap up his character arc as a whole. But even if he stays, this news actually leaves me somewhat more confident that RTD will leave him in a good place, which hopefully means a favorable resolution with Rose.