A large part of it is the flawed initial premise: His jungle wasn't that bad with the Season 3 changes. The additional ~10% base ASPD did help him a lot as well. His Q is a really good ganking tool in general. He needs some QoL changes for his kit perhaps but he was definitely not a trash tier garbage champion.
Shifts in the meta, or even just people actually trying things out, do a lot for perception of champion viability. It's easy to say that a champion is weak and needs help and completely miss what they can actually do given the right team comp, build, or even just player skill.
There's over 100 champions. It's fairly easy to overlook how good something is, especially without any direct changes to them.
That said, Volibear's ult still has that awkward cast pause right? riot pls
the big thing seems to be that every spell is an offensive one, her combo seems to be something like QREWQ.
For lane? It'd probably just be E-Q-W-Q. Set up the Blink, land a Q, blink onto them, snare them, and then Q until they die. Alternatively, leading with R (or Blinking into range for it) to pick someone off.
Her teamfight would probably be E in, W, and then ult herself. The ol' Zhonya's bait engage.
Edit: On that note, her base stats are a lot better than I originally figured she'd get (~450 base HP, ~14 base Armor). Her slow speed will make her an awkward roamer though ;__;