I think they could have been as good as the Cavs but not as good as the Warriors. Scotty Brooks was not a great coach. Westbrook and Harden are duplicate talents in a lot of ways. Neither were the outside threats that they have since become. Clearly the OKC front office blew it with Harden. He wanted to stay. They should have paid.
The Warriors are a nearly perfect collection of talent. #1 offense and #1 defense in the league. Really an unbelievable combination.