My main beef with it, is that all the last 5 champs except kaisa, have a big sometimes overly strong gimmick, zoe's being her W which is still awful to deal with when you get a favorable trade but she rng's a redemption off a minion so fk you LOL, 1000s of gold worth of utility from her W every game outside of her overloaded W she's a relatively balanced long range burst mage.
Neeko's gimick is much weaker and sadly she's built around it, her disguise and now she only sees play b/c of an on hit build abusing synergy with her W 3 hit passive, and not as a zone control mage as she was arguably intended.
Pyke has 2 gimmicks, his ult's gold share is the one that makes him viable as a support, and his inability to build health which effectively forces him to be more of an assassin, not much else to say about pyke, i would say he and kaisa are probably the more well rounded of the newer champs.
Sylas, saved the big one for last, sylas got the most outrageous gimmick, the ability to use any ultimate ability in the game, without doubt I'm sure many have asked for and disscussed putting the ability to steal ultimates on a new champ and that riot thoroughly considered it. The problem with it is this, ultimate abilities are often game changing and can take up a huge amount of a champion power budget, so a champion that could steal and use any enemies ultimate wouldn't have a ton of power budget left over in theory, however sylas has ranged poke with a slow on Q, short targeted gapclose w/ attached heal on W, A free mini-dash on E (like 1st half ekko E) that allows you to basically cast an amumu Q after. So not only does he get the utility of access to the enemy champ ults, he has a TON of utility in his QWE to use them to absolute maximum potential. Sylas is the most disgustingly overloaded champ to be released in years