As a multiclass player and condi druid amongst other things Id say my biggest problem is killing players in a row without Them Ever Being able to answer to anything i throw at Them, and Then running into somebody who is not a complete walkover. What happens Then is usually me blowing out my rotation and Then screaming "oh crap".
There is No class Imo that is hardcounter to condi druid, but firebrand, ele and scrapper can draw it out to stalemate sometimes.