Which is a direct result of the dicing + widespread NAP'ing currently in the top. If more kingdoms would threated the dicers with waves then dicing wouldn't be as profitable anylonger hence running more wars would be far more profitable.
But since we have to live with widespread NAP's then dicing will be the best option available today and then you'll have to look for either a change in the general game mechanics to improve the possible rewards from wars or live with the occasional topfeeding wave and hope that they will get spread evenly around the dicers.