Not really that shocking. They pop HotW and you know that they will start casting wraths, which when interrupted, will lock the Druid on their healing tree. That'll put them 5-7 seconds behind on healing and/or keeping hots up. Add the original 1 second of wrath cast to the start and maybe CC them after the lockout and that's nearly 14-15s of them being behind on healing because they popped an obvious DPS cooldown and got locked on cast.
my undergeared resto druid buddy nuked a warrior for a 77k wrath yesterday while i was getting outplayed by second wind. it was pretty lawls. someone link the vid of christhormann/sodas/[r1druid] playing triple resto druid with heart of the wild. now that was some good shit haha.