Picked up Warwick not to long ago, and the problem with him is not that he's broken its that he forces the game to shift around him. thats not broken.
"But... But.... I DONT WANT TO HAVE TO ADAPT MY PLAYSTYLE TO WIN AGAINST CERTAIN TEAM COMPS!" well sorry, thats warwicks ENTIRE PURPOSE.
Warick is designed so that you have to cater the game around him. It is VERY easy to do this, but the problem is, no one wants to adapt their play around something new. sure, you'll adapt your items to deal with the fed carry on the enemy team, but HEAVEN forbid you adapt your GAMEPLAY to deal with the champ who's desgined to force you to do that.
Warwick is like a good split push. If you see a splitpusher, you dont whine, "SPLIT PUSHING IS BROKEN. RIOT NERF THE CHAMP WHO IS DESIGNED TO TAKE TOWEERS ON HIS OWN BECAUSE HE TOOK TOWERS ON HIS OWN." You instead cater the game to deal with the splitpusher.
As someone who has played as and against warwick, heres what you need to do to beat him.
Play safe early, dont let him snowball his early power, or he'll never lose it
If you get low, BACK. if you dont you'll get ganked out of nowhere and be dead.
If you are trading with him early in a gank or in the jg, if you are losing health at equal rates, dont fight him. DO NOT FIGHT A WARWICK UNLESS YOU DEAL MORE DAMAGE THEN HIM. Remember, the lower he gets, the STRONGER he gets. his passive gives him bonus lifesteal when low, you need to kill a warwick fast, so let you ADC come help with a problem warwick
As a jg, he needs gold from kills/assists to get his tank items, until he does he will be decently squishy. as an enemy jg, invade him early with the help of your laner to make him gain an even greater gold deficit, you need to stop his snowball from rolling
if you do this, he should fall behind enough to be useless to his team, and then your jg, who should now be stronger then the warwick, can come invade him and make his day suck.