[@Vocalia]
Yes. If you don't buy wards as support, you're apparently the worst person on the team, regardless of amount of health healed, damage dealt, or kills. (And Witch Doctor is one hell of a murderous support character once he gets his alt. And you can give him a 1sec stun right at the beginning of the game for an, at times, easy first blood in a lane.)

There's plenty of hiding in DOTA, but also a lot of terrain destruction. Most characters can at least buy an item to remove trees to restore health, but some characters can just cut through a small forest's worth and reveal everyone there. 

Ganking drives me crazy in DOTA, because some characters are just really good for the job.