The logic behind Caitlyn rework was very bad.
I am not saying Caitlyn is op. This is not that post. The LOGIC behind the rework was not good.
No one thought this game was really that broken in Season 5. In fact, Season 5 had the largest champ pool selection at worlds by a SIGNIFICANT margin. Riot wanted to make ADCs feel more unique. That's great. Yet, 'make unique' just became 'poor more damage into the kit'. No one in Season 5 thought Caitlyn was broken or even underpowered. She was a lane bully with a bad mid game, if the game went on long enough she'd shred, there was no problem with that.
All Riot did was add a few more ways to proc headshots that can reach +1K damage. They just dumped damage onto a kit that might have been not unique, but it was BALANCED. This has generally been the issue with a lot of reworks.
The Vel'koz one was the worst. It's a 'rework' that, in all seriousness, is an embarassment to call it a rework. No one thought Vel'Koz was unbalanced prior to his rework, but true damage was just arbitrarily added to his kit. That's it. Nothing was reworked, nothing changed, he's the same champ, just put damage onto the kit.
The problem with a logic of 'add more damage' is that it throws the flow of the game completely out of whack. Lane's tilt early, and harder. There's less opportunity to catch up. Scaling champions don't get the time to scale. Lane bullies are now even MORE SO influential than before. Armor pen and cdr are available en masse. Teamfights are short. There's less opportunity to make a big play. The damage creep is enormous.
Rather than cause all champions to feel unique, it's caused more champions to feel like copies of each other, and that champion is named 'One combo, one kill.'