Abuse? Viktor is a control mage who had his burst delayed by a lot, if not for Rylais he will be garbage, his ray takes about 0.85 seconds to hit the second part and his ulti was made slower too with 2 seconds delay between the damage, he could only use his single target Q>AA burst by going ADC range which only hurts after he builds lichbane (least cost-effective item in the game) and requires you to max Q over E (Auto over Death-ray, so he can be shoved under turret) without Rylais, and he is supposed to control the battlefield not to be old GP but AP.
Azir is garbage and will probably be reworked or severely changed, nice way to prove a point of Rylais being "abused" by him, it's his only way to win now.
Riot fucked up on Cassio, Rylais overloads her kit, Q speeds her up and slow you down, E too, just a mess right now.
Honestly for the state Mordekaiser was left at, you should really stop asking for buff and worrying about his "love-hate" relationship with Rylais, every mage has "love-hate" relationship with Rylais by your logic, "love-hate" means that Morde will be forced to build this new Rylais losing stats in exchange for the slow passive, not that Rylais makes him playable because Morde has no CC, the whole item has not a wasted stats to be defined "love-hate".
Also Rylais was not changed anytime this season, last change was in 5.13 (5.22 if you count cost increase), so MYMU made it necessary on mages who got their reliabilty nerfed and a rush on those who got fucked by RoA and Tear changes.