The Hexadric Hegemony was a very hierarchical state. Older, wiser women that other Hexers acknowledged as matriarchs generally exercised firm leadership over many aspects of Hexer society.
The Hex Army was no different. Jointly managed by the six matriarchal dynasties, the strongest and proudest mech force of the Hegemony adhered to a rigid set of rules and customs.
Every change needed to undergo a process. Every action needed to be approved by an authority.
To the matriarchs, not even the best and most influential Hexer Master Mech Designer was allowed to arbitrarily add a new mech model to the Hex Army's lineup! Every single proposal had to undergo an extensive approval process before showing up at the battlefields.