You guys are forgetting some basic simple facts:
1) Blizzard makes the rules, and consequently, they made this story.  As an author, they are entitled to do whoatever they please.
2) You are forgetting of the fact that by putting down such a hero as Illidan, you, the lowly adventurer become a hero.  There is lore attatched to your name.
3) Suggestion for a new expansion: add an effort to the PvE.  Comparing by example, there are titles for PvP.  Whichever form it may be, there are titles which are held in higher regard the higher up the ladder.  And there are items and titles reserved for the top players.  Why not create a "hero" type plot for the "adventurer."  Truly more focused on a role-playing game, imagine having a 51 point talent in your tree which can only be spent upon achieving such an epic feat (which should measure more than just simple numbers; random completely on basis; more based on luck; that actually requires more skill than rinsing and repeating) .  In essence, I think Blizzard should add a "hero" type system to the game.  And it should be based on individual merit.  Similar how any real life "hero" has emerged from the rest of the crowd (i.e. Jesus, Gandhi, Malcolm X, Kevin Bacon, etc.).