Right now there's only 3 junglers maybe 4 if you count Olaf and their all tanks Skarner/Sejuani/Zac everygame its quite boring meta and not very diverse when their is over 140 champions but only 3 junglers over 90% of games. make warrior and ap junglers better Lee sin is basically unplayable without wards.
So my guess is that you think these guys are good because they are being played in the LCS a lot. The thing is, if you base the meta based on what the pros play then sorry to disappoint you but, they won't be playing damage dealing junglers. The reason is because pro play is a lot more coordinated and safe than Solo Q which will make it difficult for junglers to gank and therefore we have a meta where junglers are tanks that can cc hard or stick to targets easy.
The other reason is that damage dealing jungler are a lot more squishy which is bad in teamfights cause they can die easy and have to be careful because of that. Now you may think about season 7 when we have rengar jg in the LCS, the thing is, the only reason he was picked was because of his passive which gave him soo much damage that he could go tank instead and still deal a lot of damage.
My point: The only way that we will have a "damage" meta is if they overbuff every junglers damage so that you don't even need to buy damage items. IMO, you should probably not bother comparing the meta with LCS cause I doubt that the pros will change the way how they pick in the jungle unless Riot just makes tank items super bad.
EDIT: Another thing that made these champions better is the removal of catchup-exp. Instead of making early game junglers better it motivated players to farm up early and hit 6 as fast as possible instead of going for early ganks.
Don't forget 
i agree riot compare us whit the lcs players in solo Q even lcs players wil lose we have trols afk and some times kids we all know that ; they rly have to work on the jngl i love jngl , i like to be always in jngl rol but riot make me play mid or adc to carry my self and my team ; now a jngl when he gank in low elo instaid to go 3 vs 2 in bot he mabe be 2 vs 1 beocs of his bad teammates this is the point we are not all chalngers and master riot pls 
You're right, you just have to ignore that 
are doing better than any of those that you listed, and that Skarner and Zac are some of the worst performing junglers in the game.
So just ignore reality and anything can be true.
I like Vi. But I'm silver 4. Is Vi any good?
