Dallas are going to be insane with Rondo running the point and orchestrating things. They really catapult to legit title contenders, if they weren't already.
As far as OKC goes, they rely way too much on individual talent. Scott Brooks still can't draw up plays for Westbrook and Durant beyond a high screen, so they're way too ISO heavy. Of course, if they're firing on all cylinders, it's almost impossible to stop, but OKC's offense is becoming predictable: High screen for Durant/Westbrook, a Durant/Westbrook ISO, and a pick and roll with Ibaka for a mid range jumper.
Compare that to how fluid GSW's offense looked and how easy that makes things for Steph and Klay. What's even a bigger problem when dealing with these two is they're amazing shooters who can also penetrate and finish, so if the defense helps, they have to worry about the kick out, and if it doesn't, they have to worry about giving up easy lay-ups. It's a catch 22.
Part of GSW's offense being more fluid than OKC is because Steph is a better point guard than Russell (though not necessarily a better player) as far as running the offense goes, but part of it is definitely Scott Brooks' limited offensive creativity. Nevertheless, if Durant and Russ stay healthy, OKC are a major problem for anyone because there's only so much you can do to stop them. I still think Durant is the guy, despite how well Westbrook has played (bar last night, because he wasn't good). When Durant was on, as he was in the first half before the injury, it literally doesn't matter what you do.