Please actually read the first paragraphs to understand how the ranking system currently works. Tier 3 and 4 are not bad tiers. Stop panicking and getting butthurt.
Alright before people go full idiot mode like last time - this is STILL NOT a full tier list. I still have yet to fully flush out things or test out certain ideas I have - mainly if offensive murder junglers are a very strong choice alongside the usual tanky support.
With that said - the tier list is only stacked from top to bottom and not left to right. This means the junglers in tier 1 are all held in the same pool of strength because it has yet to be refined completely. So if Dr. Mundo and Nocturne are in the same tier but Dr. Mundo is higher - it doesn't mean I'm saying he's a better jungler.