I think the weapon upgrading needs some love. With the new weapon abilities the current upgrading system doesn't work, for instance i make a nice group of one handed axe maidens, but when i unlock the next weapon tech i get the option to upgrade their weapons and they suddenly start using maces.

So what i suggest is that each weapon type is listed separately in the weapon selection screen, each weapon is given an upgrade ability and so sword maidens could upgrade swords. Spear units would upgrade spears etc.

This method may need some new weapons adding to the later part of the tech tree, but would allow sensible control of how units upgrade.