Moonfire? Really?
We bring a Moonkin Druid and he does extremely well, although he is a bit of a mana hog (Shadow Priest to the rescue!) even without using Moonfire.
Moonfire is extremely mana-inefficient and costly as all hell for what it is, and even with Imp. Moonfire gets an very small bonus from +DMG. Starfire hits for ~580 + 132% of +DMG, for 370 mana (before reduction talents). Moonfire hits for ~1100 + ~90% of +DMG for a whopping 490 mana (again, before reducion talents), of which only ~330 and + ~18% of +DMG can crit. Even with a moderate amount of +DMG and Crit, Starfire should easily pull ahead in mana efficiency. Moonfire is handy for when you're burning down low-HP targets, but... *shrug* Especially when mana is already something of a limiting factor, adding in an additional high-mana, low-efficiency spell seems kind of foolish.
If you want a high-efficiency DoT, Insect Swarm costs 175 mana, does ~800 damage plus 80% of +DMG, and will increase your tank's survivability.
His boss-damage routine is pretty much Insect Swarm, Starfire until it drops, reapply Insect Swarm, Starfire until it drops, repeat. Wrath is handy for trash but not really useful on bosses, and Moonfire is... not really used much.