Huseby has a point. NA prolly has 2x as many fiefs as it needs. I don't think there's really any kind of organized/established strat playing clan that actually has a shortage of fiefs (besides the obvious ones that were recently rolled). So nobody really has too much incentive to really gun for someone.
Also another thing that encourages large affiliations (not necessarilly alliances, but close) of clans is that rosters of 45-50 is probably too high for NA for the current amount of strat participation. Most clans only show 10-20 of their own members to these battles, so they need to be friendly with a bunch of others to get reliable merc showings and if you go around attacking a lot of people that is gonna become a serious problem. Maybe battles, even sieges, should be capped lower at maybe 20 people for field battles, maybe 25 for villages, and 30 for city/castle sieges?