A few concerns about the preseason changes
Now before you tell me that I'm jumping the gun and that this stuff hasn't even come out yet, I know that, but I also know bad ideas when I see them, and I don't relish the idea of the game being broken for months like it is every preseason.
For example: Fervor of Battle now grants up to 60 AD at max stacks/max level. The new Colossus keystone can grant up to a 35% max health shield. Both are fine if you're planning on committing to the idea of insanely strong keystones, but if you leave the others as is (dft, thunderlords, stormraiders, etc) no one is going to take them. They're simply going to be massively outclassed. You're also leaving mages with nothing to compete with.
Secondly, it seems you just blanket buffed all of Rengar's abilities without fixing any of his glaring design flaws. In fact, it seems you've actually enhanced his design flaws. Why?
Thirdly, I like the direction you're going with stealth when it comes to Twitch and Rengar, but you have to understand why it works for Eve but won't work for those two. Range. Evelynn has 0 range. The only ability she can even use outside of her reveal range is her ult. This creates a fantastic fast paced playstyle that's great for the Eve player while not being incredibly oppressive to the target. Twitch is ranged, meaning he never has to go within reveal range (and really never should). Rengar has his leap, so reveal range or not, he will still be able to attack you with very little counterplay. Simply put, the idea will work, but their reveal range needs to be larger than Eve's.
Those are the things I think will be the biggest issues, everything else looks pretty fun. I'm not too keen on the plant things, but that's more me being afraid of change than it is me thinking it's bad design.