The main difference between the two maps is that a number of regions in Eurasia, especially in Europe, Russia and China, have been subdivided into smaller regions. Another difference is that the start time for the areas controlled is different. The Anniversary Edition map shows control as of 1941 before the invasion of Russia and Pearl Harbor whereas the 1942 edition starts with the Germans well into Russia and the initial Japanese conquests completed.
Italy is once again included as an integral part of the German empire in the 1942 game, and China likewise loses it's independent identity again and the "Chinese" units are represented with US forces.
On the other hand, vast areas are exactly the same (Africa, neutrals) or only have minor differences (USA, some Pacific areas). The economic values are largely the same and the actual combat rules are the same aside from some clarifications in wording. From a game play perspective one of the biggest differences between the two versions is that the 1942 edition does not include either National Objectives or Research & Development rules.
Overall, the 1942 edition is a stripped down version of the Anniversary Edition and should play a little faster.
The victory conditions in 1942 are also derived from the Anniversary Edition and are based on conquering Victory Cities, although the number of Victory cities has been cut down from 18 to 12. Bitter-ender players can play until all 12 victory cities are captured by one side or the other, but the "Standard" victory condition is to play until 9 are held by one side or the other. In this game the fall of the Soviet Union does not necessarily mean the game is over, as Russia has just 2 victory cities so the Axis will also have to capture at least one of London, Washington, San Francisco or Calcutta. naturally Calcutta is probably the most vulnerable on that list.
This seems to leave open the possibility of playing on even if Russia falls, especially if the USA can capture Tokyo, which may make it risky for the Axis to use a gang-up strategy against Russia.
The models are definitely a step up from any seen before in an A&A game, better than the Anniversary Edition. There are very few cross-nation models now, with every country having its own battleships, infantry, tanks, fighters, bombers and cruisers. In some cases there's little choice. The Russians never actually built their own carrier, so it makes sense to let them use the British model and a few models are shared between a couple of nations (destroyers, artillery, transports and subs) but no more than that. The models themselves are crisply made, although a couple of the sculpts have a few questionable or inaccurate details. (The British battleship turrets appear to have just one gun each and the Yamato's stern looks funky)
This is meant to be the standard A&A version for "years to come" according to designer Larry harris so I wouldn't expect to see any more changes.