When did they say the doctor can regenerate only 12 times? I don't remember that.
And I don't think they will finish the series only because of that, I think it is still popular, and although they make really long pauses between seasons, it's still profitable.
About the old series. I'm not old enough for nostalgia (given, I haven't watched more than 5 films in black and white). but I think I'll give it a try (You actually said what I expected, old series have troubles being interesting today).
Do you remember the name of this episode?
Edit: We really should add alignment, it's hard to read my messages. So sorry for that.