To paraphrase what you've said, and to retort to Munkeh111's inadvertant slight to the game:

Oblivion can be beaten in 11 minutes. FFXII has a weapon you can only get if you get to the end of the game in, like 18 hours.

Molyneux has said that the main quest can be beaten in 15 hours. However, the only people who rush through games like this are renters and reviewers. People who actually go in with a positive outlook could spend much more time with the game, and indeed must, to get a fair and complete idea of the overall experience, something rushing angrily through the story simply can't do.

So, what I'm saying is, if the game's good, 15 hours ain't gonna cut the surface, and again, if it's good, we won't need the good/evil gimmick to justify a second playthrough, or even a complete first one.

I don't recall Molyneux ever saying the non-requesite content was a mmorpg like grind, either, so that's a misconception.

I don't wanna overhype this game, but I don't wanna marginalize it with a faulty playthrough hour. I mean, MGS4 didn't need to be 40 hours long, and CoD4/Portal exist.

I think it was actually 72 minutes for Oblivion, but I might be wrong.