GW2 is buy to play and has been developed around that business model from the start. If BW wanted to move in that direction, they could, but they decided to remove the initial barrier for entry, that's their decision. Comparing what GW2 and SWTOR deliver isn't a good move since the two use different business models.
TF2...I don't see how you can draw any comparison here beyond the fact that neither cost any money to play. The games are so vastly different it's like trying to compare a squirrel to a whale simply because they're both mammals. Doesn't really work.
As for WoW's free trail...it limits you to level 20. SWTOR delivers the full leveling experience (content-wise) and access to far more of the game than WoW's trial does.
I'm not defending BW's model here, I hate it. But these aren't really good comparisons if you're trying to highlight how poor it is.