A Warwick Rework Concept
So, effectively the idea is to "Sion" him. I'm going to reference it a few times, but what I want to address is what we want in a rework. After all it can't just be a full-scale gutting of a champ, otherwise you should just make a new champ. So the rework has to be thematically consistent and keep some elements of the old kit that maintain whatever their fantasy was.
So we have to ask, what was Warwick's theme and what was his fantasy? Then, what elements of his kit are we interested in keeping or repurposing?
His theme is clearly, Wolfman. Not quite werewolf, as that implies a transformation. His fantasy is his synergy with on-hit effects but remaining a sustain based duelist. Unfortunately his duelist identity is wrapped up in just being a bunch of stats and isn't very engaging either. Still, he is a simple champion and should remain so. Giving him 7 passives and an overly complicated ult isn't the answer.
So what will we keep from his old kit? Definitely an interaction with "scent" in some way. Strong sustain. In some way strongly synergizing with on-hit effects. We also want to keep his ability to move fast in some way. Unfortunately I think his suppression will have to go, it just doesn't have much purpose. It was fine in an old kit like his, but we're moving on. This means we can give him a greater power budget in other areas instead of having him so tuned around his ult.
Passive: Law of the jungle - Warwick heals for 15% of all damage dealt.
Warwick gains 1 magic damage on-hit for every large monster and siege minion he kills, 2 for champions, and 5 for epic monsters.
Q: Survival Instinct - 30/40/50/60/70 mana, 12 cooldown, Duration 5 seconds.
Warwick fights more ferociously when outmatched.
Passive: Warwick gains 1/2/3/4/5% damage reduction for every enemy actively attacking him. Up to 30% (Does not apply to minions only)
Active: Warwick's attacks cleave, applying on-hit effects in 500 range around his target.
W: Lunatic Moon - 60/65/70/75/80 mana, 18/17/16/15/14 cooldown. Duration 6 seconds.
Warwick calls out to the Moon, increasing his bonus attack speed and bonus movement speed by 70/80/90/100/110%. Attacks increase the duration of this ability by .5 seconds up to 4 seconds.
Allies who remain within 1500 range of Warwick retain half this bonus.
E: Hunter's Scent - 5 mana per second, Range 1300 + (8% per 1% enemy health missing)
Warwick passively locates monsters, minions, and champions around him. (Indicated in the same way Sweeper currently does) The lower on health they are the further he can track them. Champions are not notified.
Warwick can activate this ability, granting him vision of targets he can track (doesn't really extend beyond just them) and alerting them.
During this time Warwick gains 20/25/30/35/40% slow resistance and tenacity.
R: Ravaging Hunger - 100 mana, 100/90/80 cooldown. Duration, 12 seconds.
Warwick attacks twice every time he basic attacks. Cooldown and half mana are refreshed for kills and assists [including on monsters] during the duration of the ultimate.
Quick Discussion
He is designed as a hunter, the kind that is regularly in the jungle, hunting for food and living life in harmony with the forest. Unlike Rengar who kills for sport and trophies. His passive is meant to be indicative of that, but designed as such he's not excluded from laning. I stress his passive heals him for all damage dealt by him, true damage, magic damage on hits, physical attacks, etc. Not unlike Hextech Gunblade.
You'll notice Warwick has 0 scalings. Of course, this was on purpose, yet there are still plenty of items that work on him. He's still a steroid machine and AD works perfectly fine with that. He scales with AS and MS and on-hits. The same items you built before are still useful on him, albeit Nashor's and Guinsoo's are less so. He's more designed to synergize with juggernaut items and be a juggernaut. The kind who runs in to a fight because he can and living through it. His abilities should allow him to engage as he wants and give his allies courage to follow him.
His ultimate was designed to be used while in the Jungle to help him clear, hence why it does so little, but also retain dueling power. I think it's appropriate as he no longer has a gap closer of any sort or any kind of CC, he just has to run at you, the very definition of a juggernaut. But once he gets there, there will be trouble. Still, he can be played against once he's there. He still relies entirely on melee autoattacks. He may seem like he has Irelia levels of CC resistance, but he doesn't have a gap closer or CC like she does. He still has to contend with knock-ups, suppression (the irony), and displacement as well.
Let me know what you think.