I hardly ever try to provoke a war. I just go to it. Last game I went to war with Isabella thrice... she would have been a very good ally, seeing she had the same religion as me. Oh well, too bad she set her cities near me, risking me to have only 3 (good) cities tops. Declared war on her 3 times... at the end, got 6 good ones, and further on, about 10 all together.
But yeah, I hate the penalty. Especially if they're the same religion as you, and they could be a good ally. Anyways, might as well just take that civ out. If you're not sure if you can defeat them, have another civ declare war on them. They'll send their troops out to defend and whatnot, and you just go in and kill them all.
I love this tactic. Stupid AI.