5 druids are fun! Yes, for PvE...

BUT for PvP it's a totally different matter. If your opponent knows what he/she is doing than you're screwed! Boomkins do not have good defensive skills. You get feared (no tremor totem), all offensive spells hit you (no grounding totem), no good way to get rid of melee (typhoon is only a cone, can't use while stunned), starfall does hurt but not while you are feared, stunned or incapacitated... All in all, unless YOU get the jump on your opponent than you will most likely have a hard time downing anybody.

Your perfect scenario is to 1 shoot unsuspecting opponent with starfire, summon treants, cast starfall and hope for lucky crits and well timed typhoons before they demolish your team.