well, I thouhgt about this idea: there must be a way to get rid of the hearth fires so I think it would be a great idea if you can get rid of it by doing this:
1) you build your yeomanry over the hearth fire(s) + you point which ones have to be removed, so that the owners of the hearth fires get a message that their hearth fires will be deleted within a week unless they move their hearth fires to somewhere else.
2)the owner gets one week time to remove their hearth fire.
3)After one week the hearth fire is removed and I can build my pallisade!

ADVANTAGES:
1) There is no point of doing this with a noob
2) Better players will have their hearth fires in their yeomanry o nobody can delete theirs
3) nobody can block anything anymore
4) If someone builds hearth fires around your hearth fire, you can just make a new account and train till you have yeomanry so you can delete the hearth fires by using your new accounts yeomanry.
PS: you should be able to walk over a hearth fire so you can't block anyone elses hearth fire or gate or something else.