Suggestion: Move the Detinets card (2 Blockhouse Wagons, +20% health for Blockhouses, Frontier Blockhouses researched for free) to Age 2, and nerf it appropriately - reduce the bonus health from 20 to 15% and remove the free Frontier upgrade. This would basically make it identical to the 2 War Huts card that Inca/Aztecs/Haude have access to (and Lakota, I guess).
Justification: Russia are in a weird spot currently - they have a strong age 2 rush, a good enough late game, but everything in between feels very mid. What this change aims to do is smoothen out their regular age 2/age 3 play, without actually benefitting their already strong rush, because the Blockhouses for that are already built in transition.
Additionally, Russia already has an age 3 card which sends 2 Blockhouses (Russian-American Company), and that one is better than Detinets, so it completely overshadows it. Having Detinets in age 2, Russia would be able to be played the same way the native American civs can be played → by sending your 2 War Huts first, then resource crates for military - still an aggressive age 2, but not a rush. Alternatively, it can be used as an emergency defensive card in case you want to do an FF or FI, similar to how Inca do it.
I think this one small change can benefit Russia’s deck/build variety greatly, and it will bring a card out from the dead, too.