Being a Druid in BC was pretty great as long as you wanted to be Feral. Resto was pretty viable but having more than one in your raid just wasn't ideal. A feral druid brings all the great utility that any spec druid would bring (innervate and combat res) with the bonus of being able to both Tank and DPS effectively in one all inclusive spec. Even in the middle of a raid a druid that had started out tanking in Bear Form can switch to Cat Form and swap out their tanking weapon for a DPS weapon and do very competitive DPS. The only thing you are going to be missing out on is the rest of your DPS gear. Similarly, if a tank died during a fight you could swap into Bear form and your tanking weapon and be a decent tank while you are waiting on the combat res for your tank. You literally are saving raids. Balance is straight up bad in BC, there is no reason to run a Balance druid ever.
In Bear form for tanking:
- Mangle on CD
- Rage capped? Maul
- Lose agro? Growl
- Use lacerate to hold agro on big pulls or keep 5 stacks up on a boss †
- Keep Feral Faerie Fire Up
- Demoralizing Roar is not a priority because Warrior's Demoralizing Shout overwrites it, in 5 mans though keep it up when you can or use it to grab agro
† Lacerate produces less threat than swipe, so swipe is always the go to spell if you're GCD is up and you don't have another button to press. However, lacerate does have its place. It does best in situations where you do not have infinite rage. For example if you are fighting for secondary threat on Void Reaver you'll need lacerate because it is an efficient spell and you will not always be rage capped.
On the pull Starfire and Moonfire can be used to grab agro on multi pulls, this is very helpful in heroics.
In Cat Form for DPS:
- Keep mangle up (if you have a Bear tank no need)
- Shred to 4 or 5 combo points
- Use the finisher Rip
- Use the finisher Ferocious Bite if rip is still on the mob, but don't use it if it would cost more than 40 energy.
- Do not use Claw or Rake
Kitty DPS is silly easy and does very well. However, it doesn't scale well going into T5 and is one of the worst in T6+. Worst is a relative term though, you will sill be doing acceptable damage.
Resto doesn't have many mandatory talents, unfortunately the remaining choices aren't incredibly exciting either. You bring a nice buff in tree of life form, but can only cast your hots. Hots should be enough if you and the rest of your healers are doing their jobs. Ideally save your innervate for a healer friend or a mage to help their DPS out.