TOR doesn't have millions of heros. It has 8.
Period. There are 8 stories. That's it. You are just one of millions who happen to be playing a particular version of that story.
Just like there is only one Revan or one Meetra and millions of people played them, there is only 1 Jedi Knight, 1 Sith Inquisitor, 1 Sith Warrior, 1 leader of Havoc Squad, etc