Warrior fits shaco way better than Devourer. He has no synergy with devourer and Warrior are just flat stats that he can use very well. The problem, however, and the reason why that guy suggested devourer is that Warrior is currently immensely underpowered compared to devourer, runeglaive and cinderhulk. Warrior used to be the dominant jungle item, but it got a small but meaningful (and deserved) nerf of -5 AD. However, after doing this, they reworked Juggernaut into the way better cinderhulk. After the nerfs, cinderhulk still outclassed warrior and devourer. Magus was also pretty OP, but the stats it gave didn't help most AP junglers where they needed help in the early game. The only really good AP junglers with it were fiddle and nidalee. This item got reworked into Runeglaive and got a few buffs(/powershifts) after release making this item way more efficient than the AD warrior counterpart, but okay, AP junglers are traditionally weaker in jungle and needed some help. However, right now AP junglers kinda outclass all the traditionally dominant AD junglers. After this, they decided to buff the final rival of Warrior: Devourer. With the release of Sated devourer, ALL other junglers are now stronger than Warrior junglers and Devourer junglers are on top. Devourer is so strong currently that it is only slightly weaker than Warrior early game but scales amazingly into lategame while warrior falls off. Devourer is actually more cost efficient than Warrior, but because of the low power that early AS brings, Warrior still wins a 1v1. For farming, however, devourer is better on AA junglers.
Moral of the story, Warrior is just way worse than the other jungle items and it shows in winrates. Shaco is currently the ONLY warrior jungler that has above 50% winrate. Many junglers that traditionally bought warrior have shifted to devourer or cinderhulk. Sadly, not all champions can do this efficiently, like Shaco or rengar.