It's just another dimension to the game. I don't enjoy arranged wars; More often then not they work against us, but they have value and a place in the game because they can get you into a war that both sides think is fair. Wars that you mightn't get otherwise, because (say) when when waving them you've chained two of their t/m's. Now they don't think the war is fair/beneficial.

Whatever options to get more wars works for me. Sometimes it's waves. Sometimes it's diplomacy. Choices are seldom a bad thing.