1. Find the druid in steath. If no hots -> stun and pop all offensive cds on him. Warrior or pally should re stun if he does not trinket yours. If he has full hots go dps. You're not going to kill him in the opener. You most likely wont get any defensive cds at all.
2. If you cannot find druid in stealth and there is mage on the team wait for mage to pop out and grip or reflect polly (reflect is the better option as the mage can blink or bos around the pillar to polly your pally.
3. against kfc going hunter is a good option.
4. RLD keep rogue peeled from your pally. hit druid as much as possible. that is your kill target.
5. ALWAYS have eyes on the druid. focus icy touch his pre hots. what until you have cds or a good amount of runes/runic power. make a switch to him if he isn't max range healing.
6. try and ams his insant root buff (mass entanglement?) especially if your pally is using freedoms for himself. But be careful against rmd you're now open to get switched on. I like to run the regenerative magic AMS glyph against rmd because of this.
7. Always have grip when you make a switch to the druid. if you don't have grip you will not get a kill.
8. know when to back off. if he gets behind a pillar that's when you need to switch.
9. don't tunnel the druid exclusively reflect traps/polys, dark sim any cc.
10. Do your best to stun the druid out of bear form.
11. cupid (ret/hunt) is a very tough comp for tsg going ret is a good call, (probably the only when he has wings up). Don't stun dr the ret if he has wings coming off (next 15 secs)/off cd. Sacing trap or reflecting trap is a must if the ret has wings. Find a spot to switch to the healer. i.e. priest running into fear, shaman trying to hex etc.
12. Lastly, spamming icy touch the whole game works well. It ooms pretty much all healers. IMO the damage increase you get from howling blast is not worth the mana loss and likeliness of getting a target stunned with no hots/shields.