Anytime I have to refer to the ccTLD list, it's usually not going to be pretty.
According to my research .SU (ccTLD Soviet Union) registrations are expensive and the Soviet Union no longer exists. The ONLY way this domain will have value is if ICANN let's the TLD remain AND You develop this domain.
If that happens, I could see this developed domain having great value.
Reg fee undeveloped. IMO.
Good luck regardless of which direction you choose. Peace.