- Build army
- Declare war on Vassals
- Make real English Kingdom
- Start to have actual fun
No but seriously, instead of having England a single region with vassals and relying on the AI to get anything done, why not alter the office system to mimick the earldoms. If possible restrict these offices to non-family members only, boom you have a better system than having a vassal that has all your land. Now you can properly build a recruitment center, develop England, and do whatever.
I guarantee you that most people will just take their vassals land in the first turns, because nobody likes vassals owning all your land.
I know I will.