If we want selling not to be too simple and rewarding, let's imagine and make the process slower — say, twice the build time — as if you're "searching for buyers". And of course it means that each ship should be manually garrisoned at a shipyard (siege at a workshop) and player needs to press specific button.  Anyway it would be cool and intriguing in my opinion.

Sometimes a commander realizes that some equipment is just redundant and no longer needed. So it was a waste of money (iron and wood), and it would be better to return it. For example, on a map with a river or sea, ships might turn out to be useless — because everything happens on land, there's nothing to transport by water, and no one to fight. My idea: what if we could return every ship to the shipyard, garrison it there, and sell it, even for half price? The same for siege equipment. Why not ?  This will provide some more possibility to get resources and change the strategy of future battles during the match.    Your thoughts ? Good ideas ?  

Some special technologies I'm thinking of adding for the Scythians: Advanced Metallurgy Forges -20% build time. Forge Technologies -20% research time. Unlocks "Goldsmithing." Goldsmithing A trading bonus, but researched at the Forge. Felt Textiles Production Civilians and Buildings +20% health. Gorytos Bow-and-Quiver System Cavalry Archers +20% attack rate. Steppe Saddles Cavalry +10% speed. Scythian Bow Ranged Units +10% projectile range.

Something to improve should be that the Scythian bow is more characteristically curvy:  

Saka/Massagetae   Western Scythians/"Royal Scythians"     Tomyris