These hordes definitely make the game a bit more interesting. You can't just finish certain factions off without setting yourself up for more troubles from them in the future. It now makes sense if the enemy faction has 2 settlements left, that you take the largest settlement first so when the final one falls, the horde that emerges is smaller. I'd be interested to see if the mods try to expand the map again and add lots more provences. That would dramatically reduce the effectiveness of the horde as a force as it would only be able to make an impact on a smaller proportion of land. Currently hordes can have enough men to take a fair chunk of land or wipe out a large part of your army.