Just a thought bubble. I'm a modder apprentice so I'm not sure if the idea(s) are even possible, let alone worth the trouble. That's where you guys come in - will it be worth it?
Four changes to try and provide a bigger difference between starting clans:
1. Add a special or resource building to the capitol province that directly relates to, or enhances / assists said Clan's special traits. Eg Craft for Chos, Hallowed Ground for Uesigi etc
2. Each clan starts with a number of arts already researched. Again aimed at their trait / specialty.
3. Each capitol starts with a castle upgrade and two developed slots. Again aimed at their trait / specialty. For example level 2 stables for Takeda and a dojo making advanced cavalry available. Or a No Dachi dojo from the get go for Date.
4. Lower the tech time requirements for Teppo (matchlock's) and make teppo Ashigaru an available option from game start or very soon after.
Aim of such a mod: To try to make each starting clan even more unique by recognising their advances and preferences. To make the start of a campaign with any given clan more than just spammed Yari / Bow Ashigaru vs spammed Yari / Bow Ashigaru.
Worthwhile?