I have focused my AR14 thinking on where it is logical for teams if they go to Russia for leg 5 to travel to for leg 6. Afghanistan, Iraq and Iran are all out for obvious reasons. Israel and Pakistan are out because the risk is too high. I think the capitals between the Black Sea and the Caspian Sea are possibilities:
Tblisi, Georgia
Yerevan, Armenia
Baku, Azerbaijan
Next would be major cities in the "stans":
Ashkabad, Turkenistan
Samarkand, Uzbekistan
Tashkent, Uzbekistan
Astana, Kazakhstan
Dushanbe, Tajikistan
The Gulf States (Oman, Dubai, Abu Dhabi, Bahrain) have an outside chance, but they(particualrly Dubai) have been used a lot in recent Amazing Races.
Of that above list, I like Samarkand and Tashkent the best. They have functioned as crossroads for millenia.
What do you think?