If you're still considering Druids, go Feral not Boomkin, at least for leveling.
Leveling 5x Feral Druids, via questing, was easily the fastest 5-box group I've ever leveled.

There is basically no down time, because with five very high DPS characters, almost everything dies immediately.
Once you get Leader of the Pack, the passive healing on criticals will keep you in good shape against anything except higher level elites.

I was using a pretty simple combo.
Assist + IWT (on press).
And a macro (on release).
#show
/castsequence reset=5 Mangle(Cat Form), Rake(Cat Form), Mangle(Cat Form), Mangle(Cat Form), Rip(Cat Form)

Didn't bother messing with facing (can Mangle/Rake/Rip) from the front or back.
Didn't bother with Shred/Ravage (from the rear arc).

I had a macro for Kitty-Charge > Ravage, but aside from PvP at max level, didn't use it.

Collection quests are relatively simple as any spec Druid.
If it is a ground spawn, you can gather while in flight form.
Meaning you don't have to clear anything, just don't totally land.
If its kill so many mobs, as long as there is a good supply... you kill very quickly.