Runes and items =/= Champions
It seems a lot of people, including employees at Riot, can't understand the fact that a particular rune or item being overpowered on everyone who can use it doesn't make champions who run it overpowered.
And as a result, certain champions have gotten heavy nerfs in response to rune/mastery/item changes, only to be left unreasonably weakened after Riot nerfs the true culprit.
It happened to Sejuani when Cinderhulk was released. It happened to Poppy when Courage of the Colossus was released. It happened to Ryze when Stopwatch was released. And the list goes on.
Maybe the people in charge of balancing champions aren't the same people who balance runes and items? It sure seems that way, the way some things are introduced with little thought put into how they'll effect their intended class.
Champions who fall like this should have their nerfs reverted or at least somewhat lessened when the actual issue is addressed, not left weaker than their contemporaries.