AoE3 and "gameplay creep" and overlapping units/buildings/design/bonus. List and discussion how to change them

IDK if "gameplay creep" would be the name. For the sake of simplciity: in Vanilla you had the Blockhouse for the Russian, introducing a "revolutionary and unique" building that combined an outpost and barrack. In Warchief they introduced War Huts so the uniqueness of Russians is no more or there're also units that simply weaker versions of others. What are your exemples? What ideas you have to change them?

- Russian Blockhouse and War Huts: (the extra 5 pop of Russians it's quite low?)
- Emissaries vs other minor explorer units (Native scouts have stealth, Chasqui can fight treasure guards and build TC, TP and embassies) Emissaries could work like AoM atlantan oracles vision (little bit random idea, but different enough)
- Gatling guns and Organ guns: the first should be better! also they have "colonial stats and should get ghost upgrades)
- Aztec priest vs Incan priestess: Aztec can fight, but you rarely would use them to do it or to treasure. Even Priestess have more ranged resist.. The feature of Aztecs more powerful rituals it's matched then by Incans.
- Falconet vs Horse Artillery: there are some numbers here: Horse Artillery it's better but more expensive and pop costing... they could differentiate a little bit it's roles?
- Skull knights vs Incan Maceman: Skull knights should be crazy good because you can only spawn them by ritual... but maceman are trainable and far better...
- Ironclads vs Frigates and Monitors: Ironclads it's a mixture and of both... and wins with being mediocre against them.

Any idea?