Dragonborn or not, you're not some kind of GOD... you're a mortal with a unique power. That doesn't mean there's nobody out there who could DO the same job as you, it just means they'd have to do it DIFFERENTLY. You may be the -one- the dragon's fear... but if someone ELSE starts killing them, you'd better believe that the dragons are going to start re-assessing their priorities.
The generic, lame-ass One Man Army hero-type is old. It's tired. There's no depth to the world, when you're the single driving force behind it.
There's a difference between the story revolving around the character, and the character being the center of the story.
Heated rivalries and bitter foes wouldn't make the game any less fun or meaningful. They would be just one more aspect of any given quest. If you don't do -this-... someone else just might. Hell, I for one feel that factions and guilds ought to be DYNAMIC. People should join, and leave, and raise and lower in rank... all as a part of the world. And these people, for whom life is always a contest of survival...
... so there's this prophecy about the Dragon Born? Yeah... big deal. It's not like I'm the Nerevarine. Or the one destined to Rule Cyrodiil. Or the Tiger-Dragon King.
You're just this guy. And you can live, or die, like any other damned fool.
Why should that make you so special, that nobody can compare? To me, -that- would be the ultimate in getting old quick.