FEEEELINGS!!!!! So many feelings! This fic is so beautiful and sad and brilliant. The song lyrics are integrated really well and they really fit the theme (it's like they're destined for Who). And so many good lines:
suicide by cosmos
big bang to heat death, big bang to end of time
legends don't have irritating older brothers
it was called utopia

And those are just a few examples. There are a lot more.