I agree that vines are awesome and can spread quickly. In my opinion, opponents who knows how to position themselves well in the arena are the hardest enemies!
Also, the druid has many rooted plants, it is very common to cast a [mwcard=DNC21] Thornlasher[/mwcard] followed by a [mwcard=DNC20] Vine Snapper[/mwcard]. So, teleporting Thornlasher is very sad for the druid.
Additionally, a Warlock equipped with [mwcard=MW1Q14] Lash of Hellfire[/mwcard] can cause a huge damage to the Druid's plants!