Question: What systems (if any) are planned?

Currently 3DAAR and several scenarios are planned.

Several systems are investigated for the far future of the SAM Simulator:

MIM-14B Nike Hercules, S-25M Berkut (SA-1), and ZSU-23-4 Shilka could be done realistic to the switch.
2K12 KUB-M3 (SA-6) could be done, after removed from service in Hungary, also realistic to the switch.
MIM-104 Patriot, and S-300PS could be done as a game not as a simulation. (based on publicly available information)

cowboy

Hpasp
Free SAM Simulator, "Realistic to the Switch"
(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/
thumbsup