Finally the war against Zara!
Now, we can start the speculation about the real opposition: the mystery civs on the other continent!
Let's just hope Arabia didn't lose too much time dallying around.
The bit about using wars to leverage the human's advantages over the AI is completely right, of course. But what we didn't see here is that, often, you only need to put the AI into war-mode for it to break down completely.
That is, phoney wars must be the ultimate tool: for a very low cost (assuming you can easily beat the AI in the field, as Sis has shown himself utterly capable of again and again) you take one single action that's almost always available that makes the AI turn off its greatest assets (regardless of whether you're threatening it with invasion or not): those teching and rexing skills...
And war weariness (perhaps the only major downside of extended warring) doesn't accumulate as long as you don't have any actual battles, or if you only have them in your own territory.
One other major advantage of letting a war drag on: you only take diplo hits for that single DoW. (In essence, the diplomatic penalty isn't for warring, it's for DoW'ing. So don't DoW, which means, don't make peace!

)
Oh, one more thing. The Ethiopian stack outside Sis' city clearly showed how the AI is often unable to raid your lands in order to force you to be the attacker. Most SoDs just sit there, debating when the right time is to suicide itself completely and with no gain whatsoever. Most raiders the AI sends aren't well supported, and thus easily killed by the appropriate counter unit. This really plays to the Protective leader's advantage (waiting for the AI units to die to your superior city defenders) - as a human on the other hand, you would pillage the countryside to force those protective units to do what they don't do nearly so well: attacking or moving out in the open.