Doctor Who "The End Of Time" question for Merlin Missy and Stinking Bishop (Possible Spoilers)

Just saw both parts. A full review will come later but I just wanted to ask the biggest question on my mind right now: I've seen on lj and elsewhere that this two-parter was VERY controversial amongst certain sections of the Doctor Who fandom. May I ask why? It wasn't phenomenal or anything but I hardly saw it as controversial as say, Torchwood: Children of Earth (which I loved but could see very easily how some could hate it). Did it screw with the old show canon in a way I'm not aware of? I was only a casual Whobie back in the day so I don't really remember if the Time Lords were portrayed any different. Were they? Is that why people were upset? Did people think Tennant deserved a better ending? (I agree, it WAS unsatisfying but it was about as satisfying as the concept of regeneration allows). What was the big deal that is tearing apart the fandom?