Hey Phlox, really appreciating your feedback on Shyvana.
I prefer AD Shyv, in part because I've off/on mained her since S3, but mostly because I like to be a champ when my ult isn't up.
As of now Shyv is the only champ in the game I can think of that who's ult doesn't cd when dead. If you changed this somehow it would buff AP Shyv a smidge more, while making games from behind as Shyv less tilting. The whole no rage regen while dead makes Shyv more feast or famine which is personally a style of champ I usually avoid.
Also what would you think of buffing the overgrowth rune for junglers? As of now it ramps much slower for average junglers, and Shyv is the only farm style jungler that appreciates tank/bruiser stats (i.e. Yi/Karthus won't suddenly be taking it). I know Sejuani takes it, but it doesn't give a lot of hp, its mostly just to activate warmogs by her second item. (Also Sej could use the tiny buff)