You're wise in your words, padawan Hermesean, I give you credit for that.
It's true, it's players who create their story, as it's actors who create life on the given stage. And a true artist doesn't need nothing apart of a small blanket to show his art. You cannot deny however that those things I talk about are true.
Game Designer should work to create a world, which first of all will be inhabited by the players. And everything should work in this direction. In WAR, from what I heard, that actually was the case (other things prevented the game from becoming great, as you pointed out). They mixed things up because of the bad balance, not because of the bad design.
Here in TOR, the lead designers don't actually get it. They talk about epic stories, yet they continue stuffing the game with pre-made content. There's never enough pre-made content, and it always gets to be eventually consumed.
For me in particular, I had a spare month, when I was in-game daily for 6-12 hours (aye, there were certain days when I got up from the computer just because my head was oozing). I was astonished by the epicity of my story, and I lived it all away. Or better, I just wanted to arrive to the end so I could actually start living. It didn't occur. I've finished my quests, and all that remained was just... grind.
Personally, I'd prefer RvR at this point. Something epic-scaled, with battles on ground and in space. With possibility to capture Dromund or Coruscant. It would give out something fresh.
The best content is the one created by yourself, and the most epic story is the one lived on your own skin. And ONLY on your skin, not defined by some screenwriter.