You guys got it wrong, actually. I am use the 'Upgrade' feature that has been implemented in official game. The difference in DE is that I am exploring the possibilities of the feature while the team focus on other things. This is the same feature that I use in DE to allow player to upgrade individual Wooden defense tower to Stone defense tower (for 100 stone and 30 sec). It's the same feature that let player make his elephants go berserk. Also, I use the same feature in DE to let the player upgrade his Hypaspists to Silver Shields, and his Macedonian Barracks to Royal Barracks.
With the Maiden Archers I explored the possibilities and made it possible to manual switch back and forth between types of weapons. It is the same feature as the towers, elephants, hypaspists, etc., but looped so the player can make the unit "upgrade" back to what it was before (in this case, back to archer from swordsman or back to regular arrows from fire arrows).
Honestly guys, looking at #252, I feel like disappointment will be mine when secondary attack implemented. And without battalion system, things are going to get messy and clicky.