I know her objective control and jungle power farm is off the sharts
I think you probably meant "off the charts", though I agree that Shyvana sometimes does feel shitty. :P
I also agree with this: Shyvana is meant to be a hybrid between a juggernaut and a diver, both of which are tanky classes, yet she has practically no durability pre-6, and post-6 she still doesn't have the best survivability either. Her passive definitely feels weak, and despite the dragon/jungling theme, doesn't feel especially appropriate for her, which is why I agree it needs a rework.
Part of the problem right now, though, is that so much of Shyvana's power is already placed on her basic abilities, which have essentially three layers of powers each: every one of her basic abilities has a core, pretty simple effect, but on top of that they all have their specific autoattack-related empowerments, most of which used to be her own passive, and on top of that they also all have their empowerments from her ult. In addition, many of these effects overlap with each other (W gives flat on-hit damage and E gives percent health on-hit damage, for example), so the end result is a kit that has a lot of its power scattered across a ton of little effects.
Because of this, I feel Shyvana could lose a lot of the autoattack bonuses on her abilities, and her current innate could instead be replaced with reduced cooldowns on every autoattack, which was Skarner's original innate. Most of Shyvana's autoattack bonuses are there to increase her uptime (Q has CDR on every auto, W duration increases with every auto, R cooldown decreases and duration increases with every auto), so it would shift her power around without changing too much of her gameplay. Beyond that, I think she could stand to have her kit updated a little further, as many of her effects are boring (her Q and W especially don't really provide any sort of amazing gameplay or compelling choice), though simply consolidating some of her basic ability power into a new innate, and giving her better natural health and armor instead, could already potentially make her feel a lot better.
