Thanks for the complement.
A straight up clone is really not part of the discussion and sits besides the bargain bin indie games as poor titles. What the uniqueness quality means is that it shouldn't be an abstract way to measure a game's quality. You can have amazing titles that are refinements of previous designs such as tracking the evolution of Mario or Zelda.
Thanks for the compliment.
It's interesting that you brought up TF2. I know people who have been turned off of TF2 following the Mann Co and explosion of items to the game. Now, it's not so easy when you see two different soldiers who could have vastly different items that in turn affect their playstyle.
Incidentally, that's how I decided to play Final Fantasy 13. I heard that the hardcore fans didn't like it and it turned out to be one of my favorite games in the series :)