By nerfing the heal fraction on his Q, you've also nerfed his late game sustenance!! Let me remind you that Warwick has NO natural tankiness besides his health regeneration, while most of the other tanky champions all have some form of built in defense (Jarvan: shield + free armor, Irelia: CC reduction + hp regen, Sion: Shield + damage reduction + hp farm, etc.).
With warwick, you literally always have to build Spirit Visage and other tanky items and generally 1 pure offensive item (Bloodrazor, Wits/Sunfire counts as half tanky half offensive). I know that lanewick is a really problematic champion and is annoying, but why did you have to nerf 20% of the healing from his Q just for that? By nerfing that, you've also nerfed how much spirit visage affects him. Spirit Visage was already somewhat weak late-game and it was only truly viable on a few champions. The only way you can improve his Q is either by spell vamp or SV. The former can only be obtained by itemizing or from an aura, while the latter affects Hungering Strike poorly now that it heals for less (the amount SV heals is based on the amount you would normally heal with his Q).
Another concern is baron/dragon. Well, mostly baron in this case. Baron can be solo'ed pretty well with WW just with Bloodrazor/SV + green elixir + blue/red elixir. People may say that solo'ing baron isn't something Riot wants as it forces early baron warding, however, you have to realise that if the enemy has someone with a bloodrazor on their team then you should pretty always keep baron's area warded since they can quickly take it out.
My way of fixing his late game sustenance is making his Q heal for 90% against neutral monsters, 95% against champions and remain at 80% for minions. That way, he's laning should be ****, while his jungle + lategame would remain really good.
Thanks for reading
TL;DR: read the bolded section