Two champions who, in my opinion, are not fufilling their side role as Riot suggested.
So before mentioning these two champions who I believe are not fufilling their role, there are many, MANY other champions who need changes much more badly than these two, (e.g Taric of course). However these two could be "fixed" with sligh changes in order for them to fufill their "side role", and besides both are dominating the meta in their main role. These two champions are Kog´Maw and Kalista.
Also by "side role" I mean: E.g: Quinn: ADC, side role would be the "Roaming ADC" thanks to her ultimate, etc. E.g 2: Graves: ADC, Side role would be the "Bruiser ADC" thanks to his "tanky" capabilities and his mid ranged AA and abilities.
Kog´Maw:
Side role objective: The Hypercarry ADC that needs great peel from allies. Kog´Maw is supposed to have a interesting gameplay involving his teamates a lot. In orded to succeed these champion needs to stay far and deal damage whenever is possible (and by that when he is safe), he will be a primary target for enemy Bruisers and assassins and his team will need to protect him from them.
Why I think this isnt happening: Riot has made recent changes to Kog´Maw since the big preseason patch, and I was astounded by the changes to Kog´Maw. Im talking about mainly the change from Q passive to the W ability. Everyone Maxes the W ability, therefore has more attk speed early-mid game, as a result this champion has a BIG powerspike in the early-mid game. This is not what a hypercarry is, a Hypercarry should be weak or very weak in the early and be able to scale fantastically to the late game. Ive been checking Kog´Maw stats, and the proof is there: Of 43,000 matches analyzed Kog´Maw has a 58% of Win rate in matches with duration of 0-25 minutes and decays to 52% in 40+ minute matches. By the way, the Win rate is big because he was recently overbuffed, however this shows that he is not fufilling his side role of THE hypercarry ADC. Link of this proof: http://champion.gg/champion/KogMaw.
How to solve it: By the way, im not 100% sure how to solve this appropiately because im not a game designer. Im trying to communicate this and why I think its not right. All i can say that recent Kog´Maw changes are controversial to what Riot said at first hand how would this champion be played as. That minimum dmg from W and the extra attk speed as apassive moved from Q to W are Early game improvements, this champion should have Late game improvements.
Kalista:
Not gonna lie, this one im not too sure if she should be changed much. Im making this post primarily for Kog´Maw, but I decided to drop Kalista in because i feel something is off in her.
Side role objective (I suppose): The "Duo" ADC. A champion that is successful by playing well with its bot lane companion, good synergy between Kalista and her bot lane companion (being a support, or whatever) is what defines her and will bring them to victory in the bot lane.
Why I think this isnt happening: I think this has happened for a long time now, almost since release. This champion IMO doesnt feel like good synergy provides her TOO much. I just played a match with Kalista, and I realized that even without much synergy with my bot laner we were able to win easily. So I figured that maybe something should be changed around here. I feel like the pact mechanic isnt as important as it should be.
This is pure feels, i have no proof at all. I just FEEL THIS WAY when i play her.
How to solve it (sorta): I think her passive is very strong, maybe tone it down a bit and tone up the synergy abilities or adding a new mechanic to them (W and R), I also feel like Q is kiiiinda useless, or just not important. i just use it to sooometimes harrass, escape by jumping walls and (the main usage) to catch off an enemy and continue my Passive chain. Well im not sure what else to include :P.