For FSO:s and historical scenarios. For example the Kursk salient which saw arguably the heaviest buildup and fighting of the entire war, a area covering Oboyan in the North, Kursk of course, Belgorod in the South. Also, there were no less than 4 epic battles in the Charkov area, something worth looking into. JG54 was remarkably stationary in the east throughout most of the war at Novgorod, operational over Leningrad, Velikiye Luki and reaching east into Soviet airspace.
Just to name a few. I find the game overall lacking terribly in covering the air battles of the ostfront. It should be known also that Kerch saw some heavy fighting too, as well as Simferopol and Sevastopol in Manstein's efforts to secure the peninsula. A map cover Kiev, Cherkassy, Dnipropetrovsk and Zaporizhzhya (don't make me pronounce those names correctly) would also open up for vast historical scenarios in both ground and air action, and what about Stalingrad (Volgograd today)?!?