I think this game mode would be particularly affective with naval combat but could also be made into a land battle game mode as well for a more casual gamemode while still having the historical elements. Each team will have a VIP that the other vessels (or troops) must protect as if their teams VIP dies then they lose. I believe this will be good as it will encourage teamwork in the game and somewhat historically accurate as the ships would be trying to protect their admiral or general on land.
For the adaption for the land mode it could be 2 generals (napoleon and duke of wellington) who have to be protected.
there would be a timer so camping cannot be abused (too much) and would be a nice casual gamemode to play after a event.
EDIT: Added a poll and would appreciate peoples opinions on why they said no or yes in the poll
This game-mode would sound pretty cool in Holdfast. I don't remember off the top of my head, but there was a server on Napoleonic Wars which did something like that, where there was one team which was Russia with the troop of partisan and let's say that the UK is on the other team trying to defend Wellington. If he died before time ran out then the UK would lose.
If it was to be in Holdfast I would imagine it would be more challenging especially for naval battles encouraging more teamwork and tactics to beat the enemy.