I actually kinda agree with all three previous posts, including the OP, as they all make valid points. There is a clear evolution (not revolution) between each “modern” edition of A&A… 1941, 1942.2, Anniversary and Global… each version is cheaper, less-complex and shorter in-time to play than the next, which will appeal to different groups of people.
The thing about Anniversary, it’s a closer-kin of 1942.2 than it is to Global, which is really hands-down the most complex, biggest and longest-to-play version of A&A by a long shot (which kinda goes along with what calvinhobbesliker said), but it is still a step inbetween 1942.2 and Global (like CWO Marc mentioned). Obviously 1942.2 also has a pretty established user-base, both by affordability, playability and time on market (like zoooma mentioned).
My personal opinion, Anniversary is the end-all-be-all version of the Classic/1942 standard formula of A&A gameplay. Global is a beast of its own, and certainly the most detailed and rewarding version, but man, the cost and time-commitment of Global is massive compared to the Classic/1942 style of gameplay. Like calvinhobbesliker suggested, I can totally see some people (self-including) preferring Anniversary over 1942.2 because they do share such similar styles of play, but 1942.2 is cheaper and has an established base, and is quicker to play, so it will always be preferred by some I imagine.