Ah, Russia. This offers quite some fun.
Unique structure: Kremlin - Unique military district or fort.
Unique unit: Cossack - Industrial era light cavalry unit. Deals +6 damage to injured units and +6 damage to units which have no friendly unit standing within one hex range (simply standalone units). The two bonuses stack.
Unique ability: Samoderzhaviye - Russian Empire has a flat 10% production bonus on all units, projects, buildings and wonders. Russian cities gain +10% faith, culture and science. Russian cities are however harder to keep happy. Low happiness penalties in cities are then increased, and unhappy city also has its flat Samoderzhaviye bonus removed until its populace is satisfied again.
Note: A player choosing Russia will sit on a throne of an autocratic Tsar. The fate of the Russian Empire will be in their hands solely, as they are the ultimate authority. Their determined and hardworking people will fulfil the Tsar's order effectively, and should the Russians find themselves in favourable conditions, they will all work on making Russia a universal hegemon - titan of industry, leader in science, cultural beacon and pious example to all world, this all in devout support of the Tsar, of course. But the player should be careful - should their eye neglect the needs of the people they rule, the Tsarist absolutism will be put in question, commands will be met with apathy, and with an unhappy populace unwilling to do the Tsar's high bidding. As such, the player may eventually fall behind the times, and instead of an unbeatable giant, they will find themselves a backwater.
Leader: Ivan IV
Capital: Moscow
Leader ability: Tsar of All Russia - Russian units receive bonus power if attacking a city centre of which is within 10 tiles away from cities originally settled by Russia. Unlocks the Oprichnik unique unit.
Leader unique unit: Oprichnik - Renaissance era light cavalry unit. Presence of an oprichnik in a Russian city significantly raises local stability (maybe at a happiness cost).
Note: Player under Ivan the Terrible (or more correctly Ivan the Formidable) will be aiming at making Russia a vast power with many cities, which they then can lead to greatness under the proper and careful use of Samoderzhaviye. Players should plan the bulk of this expansion on the Renaissance era, where they can utilise the Oprichniki in large numbers, as they can keep their newly conquered lands stable until Russia properly integrates them into their Empire.
Leader: Alexander I
Capital: St. Petersburg
Leader ability: Patriotic War - If a military unit of a war enemy is present inside Russian territory, Russia can build military units in the cities the enemy has entered 25% faster and cheaper. Russian units may pillage Russian infrastructure. Pillaged infrastructure on tiles owned by Russia damage enemy units standing on them.
Note: Heavily drawn upon the Tsar's greatest success - on turning the tide against Napoleon after the invasion of Russia, destroying his grand army, hegemony, grip over Europe and the empire he built in the process. Player playing as Tsar Alexander I will have the same capablities, provided they're willing to bleed and carefully maneuvre. Best capabilities for utilising this will come in the Industrial era, with the unlocking of the Cossacks, who, with their increased strength against damaged enemies will be dealing significant blows to enemies damaged from scorched infrastructure.
Precisely why I think Russia should have alternate leaders. Last Civ installment at least 6 Civs had different choices of leaders. So let's let Russia have the same. Ivan the Terrible is certainly a character tailor-made for this franchise. Someone to make the World tremble. What also made the World shake a bit. The Soviet Red Army. Which should bring my alternate choice for leader. Nikita Khrushchev. But I could see using Mikhail Gorbachev(Gorby). Sure a bit recent. But Gorby was charismatic but also unyielding in wanting to change things in Russia. Yet still keep her strong. But I could enjoy having Ivan as leader. But include units from the Soviet Military for unique units. Such as. T-80 Battle Tank, Mil Mi-24 Attack Helicopter, MIG-23 Jet Fighter, TK-208 Typhoon Typhoon Class Submarine. Imagine Ivan The Terrible with this military hardware at his disposal. Let the World tremble.