have a macro that will change your stance then charge/intercept depending on whether you're in combat or out of combat.
give your warrior time to hold aggro. usually one or two hits is good enough for you to unleash a fireball.
you will have problems if theres more than one mob fighting your warrior, and after one mob dies, you will have to control the warrior to at least face the second mob properly. in any case, DL Miks Scrolling Battle Text and set it up so you can get a message when your warrior gets off his cooldowns. you will need to know when you can slam, when you can WW, when you can BT, oh and when you can Exec.

and i agree with user. having the warrior as main is simpler.