First - You can't ask me for a source on my information, on the same place the information is coming from, and then throw it aside because you don't like it. That seems to be Riot's MO for the boards, too, which is a weird thing to dedicate resources to hosting if they're just gonna do that. Similarly, you shouldn't be, either. Check the upvotes, random tilt that nobody cares about isn't gonna get upvoted.
Second - Jungle having less impact early? Incorrect, unfortunately. Jungler meta is now take really strong early game duelists, gank level 2 or kill enemy jungler. Clear your enemy's jungle if you kill them and then keep the enemy team in a 4v5 for the rest of the game. Snowball is out of control due to the way Riot decided to change things, and even laners just take smite now. Jungle impact is even HIGHER than it was before.
Reds are pretty clear on what and why they make changes? So, that explains why 8 days after the patch goes live, Ghostcrawler comments on a thread complaining about 8.10 (the first red comment on a thread regarding it, btw) apologizing for the patch not being clear? Unless of course you don't mean in the patch notes. Which, yeah, silly me. Why would they focus on clarifying things in the patch notes? That's just a ridiculous concept. When Riot posts things in dev corner and PBE patch cycles come around, they get all the feedback they need from these boards (because PBE boards are just for gamebreaking bugs and such.) Surprise, they rarely if ever listen. They took a full year to deal with Dynamic Queue even though it destroyed Ranked and made people quit in droves.
As for actual hard evidence that people are quitting the game, like statistics and such.. Well, unfortunately, I can't provide that. Riot stopped showing their active playerbase a long time ago, probably when they switched up their design philosophy from "Create a successful game and be proud of it" to "WHAT THE FUCK IS A SONIC???"
P.S.
Boards are so violent and aggressive now because the lack of communication from Riot has been a rather large thing. They used to be very active on boards, always interacting, listening to feedback and making changes based off it. There's now been a very high wall erected between us and them, and while they say they read as much as they can, I feel it's still very selective, because none of the really massive issues that aren't directly tied to champion statistics (like Galio's full ap abuse) are dealt with or reverted. Ghostcrawler's post that I referenced talks about how Riot does indeed take some steps back in order to move forwards - He didn't mean reverting things, Riot very seldomly does that, no. He meant taking steps back, regressing, as a company. Which is not a way to move forwards at all.