Although I've not heard of terrain coming for it, with some of the British aircraft planned (Vampire, Meteor), you could probably make up an India-Pakistan scenario, too. (Dave needs to finish his Hunter!

Definitely pretty much any Middle-East scenario would be reasonable, too. Most of the Arab nations have the Lancer, and, for example, Israel had the F-15 (you get the F-15C in Flaming Cliffs, and a full DCS level model is under development now). They also had the Skyhawk - and the A-4C & M are also being developed.
Of course, Vietnam is the major one for most US 'pilots'. We don't as yet know if anything is planned for that theatre, but a scenario could be made up again, including aircraft such as the Skyhawk and F-100D (in development as freeware).
So several possibilities, if all goes to plan.
It's worth having a look at the MiG-21 wiki:
http://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-21
Plenty of scope there!