I liked Matt Smith but thought he was landed with some fairly terrible stories (Dinosaurs on a Spaceship, Let's Kill Hitler, The Crimson Horror, Time of the Doctor). We don't need a story arc which absorbs every single story in the Who universe. DW is at its best when it's doing standalone stories then moving on.
If I had but one plea for Moffat it's this: Please stop trying to be 'wacky.' Go back to the humour of new Season 1 (The Empty Child/ Doctor Dances' is a great example. Dark, creepy story with engaging characters but with enough levity to keep things light.
I'm really looking forward to Capaldi's run, but I really hope the 'hunt for Gallifrey' doesn't become overbearing, we certainly don't need another 'Impossible Girl' arc.