It feels like a different show to me. Probably because for the first time in the new series, neither the companion nor the doctor is consistent in season 5. and from there, it's the same companions AND the same doctor for 3 seasons. Having at least one new face each season kept it fresh, whilst still having a character from the previous season to keep continuity.
Another thing that bugged me is that 11 and 10 seems to have absolutely no link. When 9 became 10 he was essentially the same person in a different body - he remembered everything, had the same feelings for rose, had the same relaitonship with her family, etc etc. 11 seems to have forgotten absolutely everything. Does he even remember who rose is? Does he care at all for any of his previous companions? when 10 died, he said goodbye to all of them - perhaps Moffat wanted all of that closed so he could start fresh. But it doesn't work that way. Since Matt Smith joined I have seen absolutely no evidence that he and 9/10 are even the same person.
WHAT IS MORE I swear to god if I see any more spunky-fearless-flirty-scottish-bimbo from Amy I will shank someone.