Devourer and Runeglaive are proof: Jungle items are inherently unworkable
Jungle items were created in S3 for a somewhat noble purpose: giving junglers a leg up in clearing jungle camps. However, in practice, they have never achieved Riot's primary goals for the jungle (S2 Worlds had greater jungle diversity than any subsequent SEASON of League), and have created additional balance problems.
Just recently we had Skimishers Warwick, OP Warriors, OP Cinderhulk, Runeglaive Ezreal, and now hated Devourer. But this isn't an isolated incident, the jungle meta since S3 has always been overwhelmingly constrained by which is the best jungle items, and whenever a jungle item was good enough to elevate junglers it was abused by laners: Elder Lizard (Ezreal), Spirit Golem (Tops), Wraith (Vlad/Anivia), all happened in S3 as well.
This is not unexpected, and is entirely fixable: Remove Jungle items from the game entirely, and balance the jungle (and junglers) based on normal items. Isn't 3 seasons of stubbornness enough when it comes to this issue?
it has say 20 stacks and you can't enchant it until you kill 20 monsters say but you can still upgrade it to
,
,
or
. Or when you purchase your enchant you need to kill 10 jungle monsters to allow it to damage champions. And yes I do agree that whatever change Riot makes someone will find a way to exploit jungle items in unintentional ways.