They did a decent job with Poppy and Sion, everything else was either underwhelming or absolutely garbage.
Ryze: Original Ryze (as much as people may have disliked him) was the healthiest of them all in the trilogy of remakes. The current iteration requires either a completely stupid opponent or Ryze to get ahead via jungle ganks to be remotely effective... otherwise you just spam spells that do literally no damage and have an ult that is not overly satisfying at best.
Kog'Maw: The rework that Riot had to revert. That says it all... although I personally liked it and thought that was one of those champions that required you to end the game early or watch out. Kog wasn't an auto-win champ, but certainly could demolish teams late game.
Morde: Absolutely awful. Morde mains pretty much weap everytime it's brought up. Trying to force a melee champ bot lane was a mistake, giving him a pet dragon was---creative---but a mistake overall as it didn't compensate for his odd nerfs and overall playstyle change. Mordekeiser has no room in league of mobility unless he has good damage, which he no longer has.
Garen: A gimmicky ult and armor shred (which actually came later on) with his spin, combined with an odd farming tool to stack armor on his W. Garen's issues are still many. I saw that the number one Garen player in NA has decided to give up on his champion after years of play simply because it became too frustrating.
Skarner: Was overtuned to a ridiculous end for a week (65% winrate) then hotfixed...
and the list goes on...