There is some sort of scandal going on.
First you have abnormally high reviews from the "official" sources such as gaming magazines and websites (like this one)*.
Second, you have a flood of one sentence reviews on metacritic of 0 that are artificially deflating the user score, the general user score seems to be in the 5-7 region.
Third, you have us, the players caught in the middle.
I don't believe this corruption is as widespread as this article and the facts may lead you to believe, so I will offer a few alternative explanations for the discrepancy:
1) The reviewers are more objective than the players and can disassociate DA2 from DA:O. A lot of the negativity is "X feature is different/worse than DA:O", and to be fair, there is a bit that is objectively worse (some graphical issues, the removal of an intricate dialog system and multiple choices in favor of stricter controls and 3 flavored response wheel), but compared to games coming out BETWEEN Origins and 2, it has quite a bit of depth.
2) The reviewers in question are BioWare fanboys who were raised on DnD and Baldur's Gate and look more favorably on games that continue the tradition. Gaming sites/mags/whatever often send people who are interested in X type of game to review X type of game. Dragon Age is polarizing because the first was almost a spiritual successor to the much lauded Baldur's Gate line of games, and giving its sequel leniency might be well within their comfort zone.
3) Their rating system is flawed. Either because they use it improperly (i.e. giving a game that has very few (but still a few) flaws a 10/10, 100%, 5/5, etc.), or because it's not set up to give an accurate barometer (5/5 is way too restrictive) of how the game actually performs.
4) The reviewers are looking at different aspects than the players at large. The players tend to be focused on the few negatives, and how much they weigh into the whole thing. Reviewers can often look at the bigger picture, but this sometimes leads to over-minimizing the flaws in the game.
And lastly, the one nobody wants:
B: There IS corruption in the system.
It exists, don't let anyone here or elsewhere tell you otherwise. This game is the only one that has gotten people up in arms because if there is corruption and it's not a misunderstanding caused by one of the 4 issues above, it is more widespread than anyone could think. Everyone that has given this game a 100/100, 10/10, 5/5 needs to have their integrity looked at and their priorities re-evaluated. It is good, but it shipped with plain flaws that can't be overlooked. How much weight these flaws carry is debatable, that they exist is not, thus the game CANNOT be perfect. Whether it was EA/BioWare employees in disguise, promised first looks/exclusivity for ME3 and other BioWare games, or extra ad revenue, there is definitely something fishy in the promotion of this game.
*I noticed The Escapist was the poster child for DA2 positive "Critic Reviews" on Metacritic a few days ago. It has since been removed entirely from the critic's list. I don't know why, and refuse to speculate, but it is an oddity considering I did call him out for glossing over the flaws and giving the game a perfect score that didn't seem to jive with what everyone else on the planet was saying.