Riot, seriously, what were you thinking?
First, we had season 4 and Feral Flare. Then we had preseason 5 and we had Devourer. Now, in the depths of season 5, we have sated devourer. Do you know what they all have in common? Upon release, they made a certain subset of junlgers so toxic that they were almost immediately nerfed into oblivion. Now, Feral Flare and Devourer were annoying and with certain junglers, if you didn't close out the game before 50 mins, you were pretty much going to get steamrolled by the infinite stacking item and you'd wind up feeling pretty powerless against it in solo que. They also baited those junglers into farming for 90% of the game.
Sated devourer is a whole new kind of toxic. If the game isn't crushed in 25 minutes, the sated jungler become nearly impossible to deal with. They do not feel the need to farm until forever, because they get their spike very early. However, like its infinitely stacking forefathers, once it is ready to roll out, it makes you feel extremely helpless. It literally makes it impossible to duel any jungler who has sated devourer. It has effectively killed splitpushing for anyone who isn't a sated jungler.
One of the prime examples of this is Jax. Now, we all know Top lane Jax as one of the primer duelists of the game. However, he isn't the hardest thing to shut down in lane and you can still fight a jax reasonably up until 40+ minutes into the game, given that he hasn't somehow gotten fed.
Sated Devourer jax is none of that. Counterjungling is a strategy that has been lackluster and extremely opportunistic for a long time, ergo making it nearly impossible to shut down a jungling jax during the laning phase. Once he gets his sated, he is almost impossible to 1v1. After he gets his botrk, nothing can hold him off. Then he builds tanky and laughs as he does 24% of your current hp every second. That's one regular auto and one sated auto. That's not even tacking on the 10% max hp he can pop whenever. Remember, this is just the botrk damage. This isn't even counting the auto itself, or the devourer on-hit, or heaven forbid it be an ult empowered auto. Combine this insane damage output with his counterstrike, which not only completely negates autos (which most opposing split pushers use as their primary source of damage), it also reduces aoe damage by 25%. Containing a sated jax is at least a 3 man job, leaving the other four members of his team to push and take objectives with no resistance. In short, unless your team comp is specifically designed to deal with it, sated jax will destroy you if you do not decisively win before the 30 minute mark.
Of course, Jax is only one example. Yi, Shyvana, Xin Zhao, Warwick, and Kayle are also among those who can easily abuse sated devourer and just make the game feel extremely unfun. Please riot, just put this idea on the same shelf with Heart of Gold, Force of Nature, and Bloodrazor. It hasn't worked before, and it sure isn't working now. We don't want to suffer through this oppressive item style any more.
TL;DR: Sated Devourer makes a handful of champions completely untouchable in 1v1s and can splitpush you to death with absolutely no chance of counterplay.