Alexander is known to not sign peace easily, even in his favor. I'd say take advantage of long wars to rack up the experience points. A couple of double-cover meat shields and a handful of double-attack Xbows and you should be able to roll across his entire empire. The key, of course, is you can't lose any units Keep melee on fortify unless you must absolutely move or attack with them. They make better obstacles and decoys than an offensive force. 40% for fortify and healing 20 hp per turn (in your borders); as long as you are on equal tech, the AI will have a difficult time breaking through.