Like Juri said once you use DCG you go around DGen totally. This is of course fine and well for a private person, but depending on any potential clauses 1C Maddox Games and Starshoy had in their deal it may be troublesome to us now if DCG was included as replacement for DGen now (and a replacement it would be, regardless of any word acrobatics we might try).
As for my personal issues with DCG ... it would be too long to list all of them. So I'm simply stating my two biggest problems:
1.) It allows or even requires far too much influence of player performance on the campaign. I vividly remember a mission when I was tasked to attack a soviet AT gun position in preparation of a ground assault (me flying a Fw 190 A-5 in ground-attack config). Approaching the target zone I saw a long column of Panthers and Panzer IV J and began to wonder what kind of target I'd see. It turned out to be a battery (as in 4 guns) of 76mm guns. Since we were intercepted above the target by soviet fighters we were not able to put the AT guns out of action ... and the tank assault failed. Yep ... some 20 tanks vs 4 guns and they can't manage on their own?
This is a result of the way the ground war is managed. It is impossible to create a campaign following historical events since both sides are virtually always on the attack.
2.) Supply system. I know it's a difficult thing to model but why on earth did Paul choose to include
factories instead of supply dumps? Factories were, in 99% of the cases, outside the scope of the
tactical environment Il-2 can simulate and the only exceptions were the Kolpino Tank Factory near Leningrad and the Stalingrad factories in late 1942.