Whenever Gulbis talks like this, inevitably some people respond saying that he doesn't back up his talk, he's a loser, he needs to bring it... I understand that to some extent, but on the other hand, Gulbis isn't claiming that he's better than the top four or top ten or whatever. He's just calling it like he sees it. And come on, it's not as though he's ranked #400 and running his mouth.
I think there's something to the "sponsorships" reasoning, but on the other hand, I wonder if a player with the right combination of charm and honesty would actually be MORE popular than the politically correct version of himself (therefore appeasing the sponsors in another way than just acting PC at all times).
Anyway, I think he's completely right, and I think that tennis would do well to have some bigger personalities on the big stage. I'd probably love someone who showed some more personality, and also, sometimes loving to hate someone is just as fun as loving someone. What he said about Fed is so true - that the image of a Swiss gentleman works perfectly for him, but not everyone should feel as though they must adhere to that image too.