It was easy for Ten to say that he's the same man as Nine since he just got there. Eleven probably thinks of it the same way. It's tougher, though, when he looks at all of the unique things about him that are about to cease to exist. No more Allons-y, no more pin-striped suits and trainers, no more sticky-upy hair, no more brainy specs, etc. Every cell in his body is about to cease to exist, along with his personality, and be replaced with somebody else's.
I like that regeneration is a little scary for the Doctor. Even if it isn't death, as The Doctor will go on, it feels like death. That's much more dramatic than, "Oops, I regenerated! Oh, well!"