*ahem* Let me re-iterate.
I was talking about that last point as from Shirou's perspective. I mean, in the whole route of HF, he is slowly killing himself one way or another. The whole thing about the route was not just his devotion to Sakura, it's also about his losing more of what made him... him. If you recall, he can barely speak to Ilya in HF True, and his motor functions are shot completely to Hell in that ending from his perspective... of course, he gets a Deus ex Machina to make him normal again, but that's by the epilogue.
Anyway, about the route's theme, from what I understand, it was mainly about suffering to let those you love stay safe, which is why it was supposed to be bittersweet for all the route. Shirou suffers more than he has to just to keep Sakura safe, which is expounded (is that the right word?) upon in HF Normal with him Excaliblasting the Greater Grail, which results in him dying after saving Sakura and, by extension, the world.
Keep in mind, though, most of my input here is second-hand. The others that have played the route would have more to say on the subject.
EDIT: No, I'm not trying to convince anyone of anything, just stating an opinion of what I think the route's theme is.