Here are the actual ratings:This doesn't inspire confidence.
The Dark Knight - 8.5
Spider-Man 2 - 8.3
The Dark Knight Rises - 8
Avengers - 8
Batman Begins - 7.7
Guardians of the Galaxy - 7.7
X-Men: Days of Future Past - 7.6
Spider-Man - 7.6
Iron Man - 7.6
Captain America: The Winter Soldier - 7.6
X-Men: First Class - 7.4
X2: X-Men United - 7.4
Sin City - 7.4
Hellboy 2: The Golden Army - 7.2
Avengers: Age of Ultron - 7.1
X-Men - 7
Superman Returns - 7
Iron Man 3 - 7
Captain America - 7
Hellboy - 6.8
The Amazing Spider-Man - 6.7
Thor - 6.7
Wanted - 6.6
Iron Man 2 - 6.5
Dredd - 6.5
Watchmen - 6.3
The Wolverine - 6.3
Thor: The Dark World - 6.2
The Incredible Hulk - 6.2
Spider-Man 3 - 6.2
Man of Steel - 6.2
If there's one thing you should notice from this, and it's something you should be aware of already, it's that reviews being mediocre doesn't really mean much. The MCU has always been all over the place, but that doesn't stop people from enjoying them.
Folks take reviews far too seriously. It's a blockbuster, and they tend to be safe pretty much. If someone has enjoyed the MCU so far, then I honestly don't see why they'd have much of an issue with the way Age of Ultron is being received.