You may complain about early game, but late is even worse.
I know it can suck to lose games over tiny mistakes, but as it stands, there's an even bigger problem: Tanks in the late game. Since Riot took out so much power from ADC items to make room for special effects and new items, you can't pack enough damage to actually hurt anyone who's built anything. The items are all so samey you're not actually very good at much of anything. You either get deleted instantly, or tickle the enemy team before being nearly one-shotted.
The physical damage bonus on Dominik's Regards is nice, but only in extreme circumstances does its performance actually diverge from the next best thing: Black Cleaver. You'd basically need your enemy to be at 150 armor with a 500 health lead over you for it to actually do better than BC. And that's WITH crit amplifying your damage. For everyone else, it's this underwhelming, inefficient addition to your kit that's both niche, and most unforgivably, ineffective. Riot didn't like your having to break out the calculator to decide whether a bounty was "worth it," but then they turned around and made me build a supercomputer to decide whether the base/bonus armor ratio and health advantage averaged across the team makes buying DR worthwhile.
Next pet peeve is phantom dancer. Great. I take 12% less damage and I get a move speed boost. Great, now the rest of the team can delete you while you try chasing down your target since they took away offensive stats. "But Christian," you say, "It's meant for 1v1 situations!" These happen with ADC's? How often do you ever see yourself fighting someone 1v1 past the first few minutes of the game and you weren't about to die because of a gank or something? They want to make it a dueling item that lets you focus on one person at a time, but the only way for that to happen with squishy ADC's is for more damage reduction against everyone but your target, to make sure you survive the now-lengthened fight as a result of said reduced stats. And that's a bad idea, because then you just incentivize tanks to get even worse still at little cost. Maybe just give me a bigger speed boost so I can just stick better?
BotRK got nerfed. How does that help? End of paragraph.
Graves. He gets to deal tons of base damage and gets great scalings, but still no cigar. I'm not trying to be funny here. Just give him the damn thing. If for no other reason than to kill the meme.
The offensive masteries would be great ... if you could use them past 15 minutes. The problem with them is you need time; something you don't have when you're so squishy and not at all safe from a back line dive. I mean between champions like Xerath, AOE CC, pulls, blinks, charges, and just plain burst, how is anyone supposed to protect you anymore if they can't even process what happened before you die?
Between squishy, masteries, item changes, etc. You end up with a Frankenstein's monster of a lategame where you're only good at doing a certain kind of damage to a certain kind of person, and you can barely hurt anyone else.