If you read the reasoning for the Fiora buffs, you'll reach the conclusion..

The conclusion that maybe Bramble Vest should have been nerfed instead.

Back in patch 7.14 we made some changes to curb some of Fiora’s mobility, but those nerfs coincided with shifts in the meta to leave the Grand Duelist in a rough spot. In a world where Bramble Vest didn’t exist, forcing Fiora to work reach her enemies—and stick to them—made sense. In a world with Bramble Vest, however, Fiora’s dealing less damage (opponents have more armor) and sustaining less off Vital procs (Bramble Vest’s Grievous Wounds), so that handicap no longer makes sense. We’re reverting 7.14’s mobility nerfs and will keep an eye on Fiora.

Here's what is really means:

"We nerfed Fiora back in 7.14, but we also introduced a very broken 900 gold item. If this broken item didn't exist, Fiora would be decently powerful; however, since this item does exist, Fiora is much weaker, so, instead of nerfing this very powerful item, we are buffing Fiora to compensate."

This is basically what it means. Why doesn't Riot nerf Bramble Vest? Is it doing anything in the worlds meta right now besides suppressing Fiora? Why not nerf the suppressor instead? In Solo Queue it counters almost every bruiser, if not them all, being such an overpowered item.