Shyvana is overall just Garbage right now...

Ever since her repeated nerfs from when Devourer was a thing and way too powerful to nerfing her jungle clear (the one thing she's supposed to be great at), she's just "meh" at what she's meant to do while so easily countered. If you see a shyvana trying to chase you all you need is a slow because the bonus MS from her W is mediocre overall and only decent at the very start of the cast because it decays. Her damage pattern is so damn awkward it's just weird. Early game Shyvana is primarily magic damage because of her W and E (although the damage isn't great since she has to stay on you for a long time). However the scaling of her abilities are so awful that her only form of scaling is by relying on her very out of place Q ability, an auto attack reset that applies on-hit effects twice. This ability alone is what has dictated Shyvana wanting to go for the on-hit builds to burst people typically seeing a rush of Devourer and Titanic Hydra with maybe a Blade of the Ruined King tossed in there.

Looking at everything together, Shyvana is just a very awkward champion who has her identity thrown around. She's supposed to be this mighty half-dragon with the ability to transform between human and dragon forms...and her way of fighting others is by slapping them as fast as possible. She can breath and throw around fire while also surrounding herself on a ball of flames to engulf those who dare go near her....and she mostly hurts by slapping.

In all honesty I'd rather see her Q changed and the sort of forced synergy with building for on-hit in the rest of her kit thrown away and replaced with something else to make her more of an AP Juggernaut in game and go for more of the fire-y half dragon fantasy that uses the flames from her birth-given dragon DNA. I have no idea what would be a good replacement for her Q but I'm confident with how beautiful the champions have been turning out from the small one-off updates are, that Riot could figure something out.