Agree with everything you said, OP.
In my campaign, after giving the dragon banner to khuzaits and them declaring war to all empire factions right after that, they were literally destroyed in no more than 3 weeks in-game, going from having all of their starting cities and more to just one castle in that time. Pretty they only sent one army each and just steamrolled through. Right after that, most of the lords defected to other factions, leaving only 3 clans (including myself) in the faction.
Obviously, declaring war on 3 factions at the same time isn't the greatest idea, but still, just being deleted off the map in less than an hour of gameplay isn't really fun.