Talented into eclipse I've been using this sequence:

/castsequence reset=combat/target Insect Swarm, Wrath, Starfire, Wrath, Starfire, Wrath, Starfire, Wrath

With this my boomkins dps has been on par if not better than the rest of my team. I haven't tested a straight wrath spam since level 55ish so I'm not sure how it would compare.