My thoughts:
BOT LANE:
Before touching ADCs Riot should look to stop the everybody dives bot meta we have going right now. I disagree with ADC's all being weak because there isnt a single class that would be able to do anything about getting 4 man dove. Mages going bot lane is cool and its even cooler that it happened without Riot forcing it. Riot should allow them to stay but make sure there are still some viable marksmen.
ADCS:
If all the diving stops and things still suck for them then yeah sure go ahead and buff away Riot. Also Caitlyn could really use a nerf regardless of how the class is. She's sitting on a 30% play rate and 52% winrate. Why would you pick anybody over her right now? The whole argument of "Shes the only one that isn't trash" is bullshit. She's overpowered and impossible to punish. Runaans Hurricane is also really in need of nerfs.
1ST TURRET:
remove it and come up with something else. All this does is snowball games too hard.
MID GAME:
I dont know if this is just me but I feel like Mid game is extremely toxic right now. 1st tower goes down and suddenly everybody on the side that took it is just rotating around the map, taking everything and starving out the other team. It's very anti-fun.
RIFT HERALD:
This thing hasn't done shit. It was introduced to try to make playing around Top Lane a viable option. It hasn't even come close to doing that. At all. In the slightest.
ASSASSINS:
Giving out some minor buffs to a few wouldn't be the end of the world. Talon and Fizz are kinda weak, a tiny buff to both could be nice. I think the rest of the problems they have come from poor itemization.
SUPPORTS:
What the hell happened to Riots focus on making it fun? All that happened was they put more supports in the rotation for a few weeks (which did nothing) and we haven't heard anything else since. Redemption needs nerfs badly, Locket probably does too.
AUTO FILL:
This still sucks. I wish it could be removed.