Although so far that hasn't been the case
Story arc wise, Danny, were you aware that RTD has told us that this year features no arc 'word' (e.g. Torchwood, Bad Wolf, Mr.Saxon) but an element from every episode,
"whether it's a person, a phrase, a question, a planet, or a mystery," builds up to the grand finale! "
You've got to watch and listen closely. It's been seeded for a long time, with small but vital references going all the way back to Series One." Man, this series is really gonna be awesome!
This calls for some speculation! Shall we call them "Arc Points"? We can all try and spot it each time we watch an episode. Here are my guesses so far.
Partners in Crime- Can't remember it enough
Fires of Pompeii- "She's coming back"
Planet of the Ood- "Every song must come to an end."