I haven't read the God of War Ascension reviews, but every other God of War is the exact same yet they've all got high scores. However, watching the first 30 minutes of gameplay Ascension and seeing that it's more diverse with amazing graphics, I don't see why this one shouldn't have got overrated review scores as well.
But yeah. I'm not really a fan of God of War, but Ascension looks better than God of War 3 to me. Here are some major changes I've noticed that are for better with the series. The climbing. Ever since the first God of War, the climbing has been nothing more than a specific part of the wall which Kratos slams his blades into and scales the wall. Ascension took after Lords of Shadow, which uses Uncharted's method of scaling locations. Another noticeable change is there is no quick time events which is a welcome change.
So having played the rest of the consoles games and viewing the first 30 minutes, my view of the game in comparison to the others is favorable. Obviously this may or may not be my opinion after playing it but my notion is it will atleast be as good or better. Like was mentioned earlier in the thread. Sony probably isn't paying them off so the score isn't 10/10 everywhere.
About the topic and OP's post, how is an average of 70+ mediocre and bad?
I do want to say Twisted Metal is amazing. Aside from the poor netcode which killed whatever community the game may have had, the game is a masterpiece and one of the best games this gen. My personal favorite Twisted Metal followed closely by Black and 2.
*edit*
Besides. Whether a game is good or not is entirely based on opinion. God Hand and Brigandine Legend of Forsena are great games.
God Hand's 3/10 review from IGN. http://www.ign.com/articles/2006/10/10/god-hand-review
Brigandine's 3/10 review from IGN. http://www.ign.com/articles/1999/03/05/brigandine-2
Here's a review from Gamespot in which the reviewer focus' half the review comparing the original Wild ARMs to Final Fantasy 7, spouts out misinformation about the title, then spends a two paragraphs bashing Wild ARMs 3 for not havinig voice acting and still having random battles. Coincidentally, just about every RPG released that gen didn't have voice acting and had random battles, and many were highly praised. The game did get a 7.5 which is a good score, but the entire review was just poorly written with the constant bashing of the original with comparisons to FF7 and being attacked for not having features that other RPGs during that time frame also lacked. Coincidentally, while it was a different reviewer, Suikoden 3 which has no voice acting and still had random battles received a 9.1.
Wild ARMs 3 Gamespot review. http://www.gamespot.com/wild-arms-3/reviews/wild-arms-3-review-2895567/
Sometimes you'll come across a review like Yakuza 3 which recieves an 8.5 and how the reviewer saying how much of a fan of the series he is playing the rest of the games. The exact same reviewer reviews Yakuza 4 and gives it a 6.5, stating that the game is too much the same as its predecessor. From the review and how much he's bashing it left and right, you'd think he hated the series. If you were a fan of the first two, then what happened to the game being the same when you reviewed Yakuza 3? Infact. Yakuza 4 is more different from the series than the third one is since you play as four characters who play fairly different from one another.
All that being said, different reviewers are going to have different expectations on what should be done and rate it based on those opinions. Or if you are to look back at that God Hand review, maybe the reviewer took a personal vendetta against the game because he sucked balls at it or maybe he legitimately disliked the title.
The only thing scores should be about is whether there's the possibility of it being a good game. With how the review industry is, if it's a 7/10+ then more than likely it is good or atleast decent. If it's 6/10 there's the possibility it's still good, but 6/10, even though is a good rating, is a bad rating with the way scores are being passed around now.