In my mind, it tried too hard to tie up all of the Eleventh Doctor's loose ends and include every enemy he ever faced, ending up with a nonsense mess of a plot. The only good part was the regeneration (though I hated defeating the Daleks with it - you wonder why the Time Lords didn't just blast regeneration energy at them during the Time War if it was that easy), but even that seemed a bit forced, trying to be so emotional.