Whilst it is obvious that your review is very well written and intelligently crafted, i have to disagree with your point that Gorillaz (as a musical project) are not worthy of being mentioned among some of the more interesting acts from the past 10 years. I don't really agree with this release appearing after only 10 years and 3 albums in to their 'career', and then only concentrating on their commercial singles. It is pandering, sadly, to the populist and Christmas markets, so 3 stars is about right for the concept here. But the music is better than three stars, even the most 'pop' moments. Gorillaz are at times disposable and shallow, but sometimes that is the point, and part of their charm is that they can reference seemingly throwaway themes in their music in a way similar to sampling but which will actually draw your attention to much weightier ideas and issues. I have found their albums good enough to warrant investigating their two b-side collections and their is some fantastic music to find there.
Overall, songs like Hong Kong, Empire Ants, Faust, We Are Happy Landfill, Demon Days, Cloud Of Unknowing, Stop The Dams and i could go on but I won't, make me think this is more than just an ego-massage for Mr Albarn, but a useful outlet for a raft of songs and ideas that he wouldn't have otherwise released under his other projects. And I'm very glad he has, because I think they offer genre-crossing, culture-clashing music that can poke fun at itself whilst also being types of modern hymns. Modern life is rubbish for the most part, but I find Gorillaz frequently find beauty in the mundanity of it.
That said, I respect the angle that your argument comes from.