The spawn rates should be carefully tuned, per continent, so that, at least for the time being, they become either nothing more than a useful way for knights to blood their swords during peacetime, or a real, serious threat that causes realms to shrink.
The former should not interfere with PvP conflict, but will allow a certain amount of extra action, hopefully especially for new players. The latter will, of course, interfere with PvP conflict to some extent, but will also increase the nobles-per-controlled-region ratio.
Anything in between those two levels will be a detriment to the game.
Poll