If you mean taking camps behind someone's back, it's still a thing.
If you mean outright killing someone while they are clearing their jungle, then it ideally will never be more rewarding then it already is (and according to people like you who cry about how OP devourer is, then it will be extremely rewarding because it makes them take much longer to get sated) because it's inherently toxic.
Unlike laners, junglers don't have minions or turrets for vision or protection. If they die to the enemy jungler they can't just camp under turret, soak XP and wait for a gank like their laners do. They keep falling behind and have to spend what little gold they have on wards against aggressive counterjunglers, and even if they see the enemy coming it's often too late because they have taken too much damage from their camps and best case scenario have to walk away and let the enemy take the camp that they so kindly leashed for them.
And it doesn't take skill either, not in the slightest. Sitting in someones jungle and waiting for them to tank all the damage from their own camps just so that you can hop the wall and kill them while they can't fight back because they are at 50% HP is literally the pussiest thing you can do, especially if you are a champion like LeeSin or Shyvana who automatically wins fights against most junglers early game to begin with. Any succes you have with the strategy is purely because you got lucky in soloQ and your opposing jungler has laners that refuse to help him score an easy kill on you while you are in his jungle.