Let's think. We have '44 Allied and '44 German hardware (with some '45 stuff in changelog). Late Western Front (Battle of France, Arnhem, the Bulge, Hürtgen Forest, crossing the Rhine at Remagen, and so forth) would not need so much in the way of new units or weapons mostly only new statics (British, US and German paratroopers would be perhaps the most important new additions, though they could use "placeholder" skins; maybe M26 Pershing for '45 maps, but it was so rare that it's not strictly necessary; Thunderbolt, Lightning or Mustang as the American ground support aircraft would be a nice surprise). This I would see more as a "2.21" or "2.25" rather than completely new version, since it would build on 2.2 contents and gameplay.
Of course, there's the Italian front, but that could be left to certain mappacks (FHT? WaW?), updated with 2.2 stuff, maybe adjusted after a couple of "theme weekends" like the one we just had, and then offered to the public (if the mapmakers would be so generous to the community).
The next big thing - 2.3 or 2.4 - would IMHO logically be the Eastern Front, perhaps built "backwards", from late-war towards early war, since there's already plenty of late-war German hardware available (early Eastern Front would require extensive reskinning from African colours to Eastern Front camouflage).
I'm not so keen about the Pacific. It would offer mostly infantry combat (tank-to-tank would be rather frustrating for the poor Japanese), while naval combat has been said to be problematic. Also, it has been rather overcovered in a million other FPS's already. Sure, it would thrill the Americans. The Europeans? Not so sure.
Eastern Front, however, would truly be a "forgotten" (from the American, not European point of view). Plus it would offer huge variety; from epic tanking on the open steppes (Prokhorovka, anyone?) to infantry-heavy cityfights (Berlin, Stalingrad) to chaotic skirmishes in thick forest (me wants the Finnish front, too!).
