Balance weights:Most of the stats are similar to what Resto needs, so I'm not going to revisit everything I talked about last time.
The one big addition is Hit Rating. This used to be "spell hit" but this was merged with melee hit along with all the other stat normailzation that came with 3.0.2. It's a confusing stat. The WoWWiki article has a comprehensive definition. But the stat stems from the fact that there is a static % chance for your spells to miss, based on the level difference between you and the boss you're fighting, as follows:
Boss type Level Base % chance to missTo look at it another way, without hit rating, your DPS will go down 6% against Heroic bosses and 17% against raid bosses. That's huge!
Heroic 82 6%
Raid 83 17%
This miss chance is reduced by talents and debuffs. Moonkin should always take 2 points in Balance of Power, which cuts that miss chance by 4%. Furthermore, Improved Faerie Fire will increase your hit chance by 3%. (There are buffs from other classes that help with this too.)
Even with those in effect, your miss chance on raid bosses is still 10%. That's why you need Hit Rating. The goal is to reduce your miss chance to 0%. >WoWWiki has a complete analysis, but generally the magic number for a Druid with Balance of Power and IFF will be 263 hit rating.
Hit rating has a hard cap: once you have enough to reduce your miss chance to 0%, more hit has zero benefit. That's why it's a funny stat to weight: it's hugely important until you hit your cap, but more is worthless. But adding Hit can increase your DPS by 10%, with no other improvements; that's a huge benefit.
Otherwise, your Balance stats are very similar to Resto. In general, MP5 and Spirit are worth less, because mana regen is somewhat less important. DPS can stop casting for a few seconds if necessary, in order for mana to regen. Healers generally don't have that option. Intellect also adds Spellpower through Lunar Guidance, raising the overall importance of Intellect.
Crit Rating and Haste are much more important for Moonkin. Every damage spell you cast, except Insect Swarm, has a chance to crit. That's a huge increase to your damage, so you want a good bit of Crit on your gear. Crits also have knock-on effects: they will speed your cast times through Nature's Grace, and to regen mana through Moonkin form. (Increased crit chance also adds to the value of Intellect for Moonkin.)
Unlike Resto, most of your spells (notably Wrath and Starfire) have significant cast times. Haste helps with that. Haste also reduces the time for a full channel of Hurricane, landing its full damage over a shorter time. So Haste Rating will increase your DPS quite a bit.
So to summarize: Moonkin need Hit Rating, probably up to 263 total. They want more Intellect, Haste, and Crit than the trees do, but less Spirit. MP5 is also not as important.
But having said that, your Resto gear is not bad balance gear at all. If you respec from Resto to Balance, you can start with your Resto gear and you'll do OK. The most important thing when you switch is to look for Hit Rating. I'll add a post soon with easy sources of Hit Rating gear.