Not really. Both oblivion and NWN aren't hack and slash RPG's. Granted, they feature a lot of this, but they are still normal RPG's due to what else they feature.
A Hack and Slash RPG that can give it a run for it's money might be Titan Quest. Very similar game, a lot of better and cooler things in it, but also a lot of downsides. And so far, I'd say Titan Quest and Diablo 2 are equal in quality and gameplay value. This is Including Lord of Destruction and Immortal Throne of course.