I Disagree. A game should get a perfect score if there is no scope for improvement. Such a game doesn't exist. Besides, what's the problem with giving it 9.8 ? They also gave GTA 4 A 10/10 SCORE. Was it a perfect game ? No. You'll find many Mods that make it better.
Please read the EG scoring policy "Does 10/10 represent perfection?
No. However, a 10/10 score does mean that we recommend a game to everyone."
If you read the review you will see that the game is scored only on it's single player. The multiplayer could be bad or good, depends on the guy. It won't matter a jot, the single player remains a phenomenal experience and the multiplayer shouldn't take away from that (the same way that not having any multiplayer shouldn't take away from a score).