So those are his abilities. They have problems numberswise, as I've listed. You could of course fix them with just numbers tweaks, but I think this would be doing a disservice to Warwick and Warwick players, as it wouldn't fix the fundamental issues with WW's kit.
What are these issues? The issue is with his damage types and his scaling. WW's skills and passive all do magic damage, but not enough to justify building him like a mage. Thus, he never gets spell penetration, and his ability damage languishes. Meanwhile, he only has two abilities that scale with his own gear: his Q, which scales ONLY with AP, and his ult, which scales ONLY with AD, yet does only magic damage! In other words... Warwick is like a hybrid, except instead of benefitting greatly from both AP and AD, he benefits hardly at all from either.
What is the net result of this? All Warwicks, when they aren't building pure tank, build on-hit. This doesn't help his Q at all, but it does synergyze with Hunter's Call and his ult. But wait, even though his ult benefits from on-hit effects, it doesn't scale at ALL with attack speed, which all on-hit items have! In fact, the more attack speed you have, the WORSE your ult becomes compared to just autoattacking. After all, at the attackspeed cap you lose almost five autos in that 1.8 second suppression... which probably does more damage than your ult, which only has a 2.0 AD ratio and not spectacular base damage, ALL magic to boot!
So overall, if you REALLY want to fix WW, make his abilities scale in such a way that WW has something to build towards. Nowadays, it'd honestly be better for him, metawise, if all his kit just did physical damage again, because armor pen items are so good, and his ult would completely apply black cleaver stacks.
An easy way to fix the reverse scaling of his ult, and give it some oomph and have it synergyze with Hunter's Call instead of just wasting his buff duration would be to just have him autoattack while doing his ult in addition to his ult stuff. Give that ult an AA reset too, and bam, Warwick has some bite again.