You can't compare this product to a Blizzard product. There is a reason why everyone always talks about Blizzard products and that is because the company has raised the bar so high in the gaming world that nothing else really matches up. Skyrim is cool for what it is tho.
I disagree. While I agree that comparing Blizzard to Bethesda isn't the right way to go, I'd say it's less because of how high Blizzard may or may not have raised a bar but because they're making entirely different types of game. They are on opposite ends of the RPG spectrum. Elder Scrolls isn't about epic stories, or amazing, challenging combat, it's about the world and the 'do what you want, be who you want' approach. It's taken open world from a perk, like in GTA games to the primary design principle, and it's damn good at it.
Blizzard, however, focuses much, much more on the combat. Story's there, certainly, I mean, I bought the Book of Cain, Diablo's got lore, Warcraft's got lore, Starcraft's got lore, but it's a bit like a fighting game, where, excepting Warcraft (starting with 3), and maybe Starcraft 2 (I never played), the story has very little actual impact on the game, other than a justification for the events therein. Their big focus is on the gameplay. Diablo is a pretty straight forward, but well done dungeon crawler. I've known folks who refuse to call it an RPG because the 'roleplaying' involved is all about which little guy to click on and kill with your axe next. WoW's a little better here, and, being an MMO, has an open world by necessity, but the emphasis is still entirely on the gameplay. There's narrative, there's reasons for killing who you're killing, but I've never seen someone keep an in character diary of their WoW character's attempts to just be a normal person and put that entire 'dragon' business behind them that actually referenced in game events.
Neither's doing it wrong, and both are very good at what they're doing, but comparing one to the other, or thinking that you can take something from one and get it to fit neatly into the other is folly. It's transplanting a chimp heart into a human. Both are higher primates, and there's basic structural similarities, and you could probably get it to work with enough effort, but it's not as simple as taking one out and dropping the other in.