Oh dear, someone got Justiced. [garen-swing]
One of the goals of the Mini-Rework was to allow Garen to be able to access Conqueror, as before, he was one of the Fighters with the WORST synergy with it, despite it being a so-called Keystone for Fighters/Bruisers. His E being able to stack the ability comes from the fact that his E is his most often used skill (He's called SPIN to win for a reason after all), and how before it only gave a single stack of the ability (Both before AND after the Keystone got reworked) despite the fact that the skill/attack hits multiple times in a single use. He was a Fighter, yet he was essentially locked out of the Keystone supposedly MEANT for them.
There was also the removal of Villainy, and the AS scaling (I assume that's what you refer to with this:
where he just spin and be twice the speed of any champion for some reason.
It was given to him to open new itemization opportunities (Though it's essentially forced his former bread-n-butter item
OUT of his itemization instead for
) but after numerous tests, his damage output largely didn't change. People just mysteriously forgot how to play against him.