Why can't Renekton's W go back to applying damage/on-hit all at once? Is the Fervor bug still here?

**Before, Renekton's W applied all instances of damage and on-hit effects at once. ** -This made it very smooth -Animation Cancelling went smoothly as well and wasn't delayed -it made it easy to gauge his damage -and it also opened up certain builds like BotRK Renekton

The problem was, with the intro of the Fervor Mastery, Renekton's W was bugged with it and dealt an extra 400 damage. This led RIot to change his W

**Now, it applies the damage and on-hit effects separately one after another. This made Renekton's W very clunky, ** -it made animation canceling with Tiamat horridly slow, -it was very hard to gauge burst, -it made you lose AOE damage/wave clear from Titanic Hydra/ Ravenous Hydra if you killed the target in the first swing (which can easily happen if you activate Titanic Hydra's active for the first hit) If the target died in the first or 2nd strike Renekton would just freeze there and look stupid -and it killed a favourite build of a lot of people: BotRK Renekton, which because of it hitting separately with % current HP damage, it made BotRK do 25% less damage

That being said, why can't Renekton have his W back to it's original state after so long? What reason does riot have to keep him with this clunky new W? Is the Fervor bug still here? If so, why is it so hard to fix?