Why does Druid have it's own group? [Raids]
It’s basically to avoid boon priority.
Druid deals almost no damage himself, making all the might, fury, quickness, blah blah redundant.
To maximize the DPS – you want the remaining 9 people fully stacked and having the ranger in his own (3rd) group makes it easier to happen.
His heals have a unique way of prioritizing and that’s people with least % HP.
Also, Glyph of Empowerment is more or less melee range and druid is often held at ranged duty (Green circles or what not). That means a lot of condition-based classes accompany him and for that he may as well prioritize the buff randomly.
Just like Frost and Sun Spirit.
“Observe, learn and counter.”
Nike from DnT posted a top 5 raiding mistakes video, and putting druid in a seperate group is listed as one of them. Check it out on youtube for his reasoning.
Most groups already bring enough buffs for each group to cover itself, and putting the druid in a specific party allows you to tailor who their buffs are going to. Because heals go to players that need them, him being in a group will only alter where the GotL stacks are going when people are taking lots of damage.
In general the druid being in a group allows your damage to be higher by prioritizing them to whoever takes the most advantage.