Non-State Groups
North Caucasian conflicts are too complicated for just two coalitions, and unfortunately the non-state groups are conspicuously absent from DCS. The separatist governments (Abkhazia, South Ossetia) are the most obvious omission, but inter-governmental missions (EUMM, OSCE, UNOMIG) are missing too. Not to mention the various militant/terrorist groups in the region.
The way it is now in DCS, it's pretty difficult to recreate scenarios typical of low-intensity conflicts in the North Caucasus. In real life, there are so many competing groups, and their interests are never completely aligned with NATO or Russia. At the very least, it would be helpful to have a neutral coalition and another "catch-all" insurgent faction added to DCS.