The meta jungle champions are the strongest ever. Patch 7.1 doesn't fix that at all.
http://na.op.gg/champion/statistics
If you click on "learn more" next to win rate, it lets you see all the jungler win rates for the entire patch. Champion.gg only collects data for a few days.
What the data shows is that very few junglers have over 50% win rates right now except for the top 10, and even within the top 10, every champion except the top 5 are hovering at around near 50%. The jungle champion pool right now is 37 champs. The difference between the highest and lowest win rates is over 10% (54% for Ivern, 43% for Diana). This is unprecedented.
The top 5 (Ivern-Shaco-Khazix-Vi-Nunu) on the other hand, are at 52%-55%. In particular, the top 3 are at 54%, 54% and 52%, respectively.
This means that it isn't junglers that are too dominant, it's that the meta junglers are so powerful, they dominate other junglers. If the enemy picks a meta jungler and your team plays an off meta jungler, it gets much harder to win the game starting in champion pick. And the definition of off meta has expanded, from "brand jungle" type things to "shyvana" or "sejuani".
Now what is happening in patch 7.1?
The high win rate junglers are not getting any nerfs at all. The only meta jungler to get a nerf is Lee Sin, but he's not even top 10 in win rate right now. Although historically Lee has always had a low win rate, a nerf to a low win rate champion while simultaneously the top champions not being touched is very strange.
The other jungler to get a nerf is Shyvana. Shyvana is a 50% win rate champion that relies on fast farming, yet her strength - fast farming - is being nerfed severely.
In previous jungle metas, it was an entire class of champions that was strong at once in solo queue. In Cinderhulk meta, it was true that Cinderhulk tank junglers dominated, but Cinderhulk users ranged everywhere from pure tanks like Sion, Sejuani and Amumu to tanky fighters like Skarner, Hecarim and Volibear. In addition, anyone could buy cinderhulk. In the carry jungler meta, you had Sated Devourer junglers dominating, but there were also very strong ranged junglers like Graves, Kindred and Nidalee, as well as low income disruptors like Nunu.
But now, more than ever, a tiny set of champions is completely destroying all other champions, and little is being done to address that.
The jungle EXP nerfs do not impact the top junglers. They still farm faster than the non top tier junglers. They still gank better. They still have ridiculous synergy with new masteries.