I'm not sure Kawhi really belongs in that group. He was terrific in Game 4 of that series in OKC (7-8 from the floor, 3-4 from three, with 9 boards), and while he didn't shoot it well in Games 5 & 6, he wasn't exactly a liability on the court for the Spurs.
Danny and Tiago seem to be strengthened and more confident after the playoff battles they've been through over the last couple of years. There were definitely some guys on that 2012 team who appeared to be not quite ready for a stage as big as even the WCF. Now, those guys have battled through 9 playoff series over the last 2+ years and have had to perform well to win some pretty high-stakes games in some pretty hostile environments. There are some special players who don't need experience to play well in those cir stances; there are others who need to go through it and learn that no matter the stakes and no matter the environment, it's still just basketball (you would think that anything pales in comparison to Game 7 of the Finals and all of these guys have been through that situation). I think Danny and Tiago (from my vantage point) fit that latter category. Their experience and poise are a big reason that it's silly to say that the 2014 Spurs = the 2012 Spurs.
OKC might still get this done, but they're going to have to be remarkably good to do it; I don't think they can count on the Spurs to get shook by the surroundings.