Boomkins are in my opinion the most effective class in terms of landing kills, but unfortunately I have yet to see a Boomkin that actually plays the class properly. Every single one just tab DoTs all game and sure they top the charts by 50k, but they helped land a grand total of 0 kills throughout the game. A boomkin that actually used starsurge more than 5 times per WSG would probably be the best boomkin in the bracket, honestly
Ele Shamans are a close second, they are in my opinion harder to play and SHOULD revolve around the utility they bring instead of the damage they do. Most shamans I see have the same mentality as a lot of Boomkins, they spam damage all game and try to top charts when they can be purging, shearing, and using everything else they have to offer to help the team land kills instead of landing kills on their own