Kog's current state is an express contradiction of his fantasy
Meddler said that Kog is meant to be the super sustained damage champion that your team protects over an extended period of time.
Yet his W only lasts for 6 seconds and remains off for the next 7. That means he'll crap out half way through most team fights and then be relegated to lobbing Ults or moving into basic attack range to proc his Innate.
If I wanted a mostly immobile champion with a giant burst of damage for my team to build around, why wouldn't I pick Miss Fortune instead?
There's an easy way to fix this.
Axe Koggy's suicide bomber Innate (it's hilarious and strong, but it doesn't fit with his kit) and replace it with the double attack speed and %HP damage portions of his W. Then tweak the W a bit to make it more interesting than a simple source of attack range. This would allow Kog to actually fulfill the crazy sustained damage fantasy Riot wants him to provide.