Nine didn't so much break my heart, it was that how he regenerated having finally broken through his Time War PTSD and was able to smile and laugh and rejoice again ... and then Ten spent his days moaning and groaning about the Time War. So Nine's breakthrough was ... pointless? Fuck you, RTD.

That's the one aspect of Ten's characterization that really bugs me. His journey is the exact opposite of Nine's and it's depressing. I suppose they did that for the "pretty-boy angst" factor? In a lot of ways, Nine was a better man than Ten, even with the limited episode count.