In my opinion, J4 doesn't have the strength to compare to the current meta champs ( Garen, Darius, Fiora) in the top lane. I might just be building him wrong or playing him wrong, but here's my build for reference. Dead Mans, Titanic Hydra, Randuins, Black Cleaver, Banshees, Mercury treads/ninja tabi. Can anyone shed some light on whether J4 is still viable in the top lane or whether he has been made unplayable due to the buffs of other top laners now.
Nobody has the strength to compare to those champs. Wait till after further nerfs to those champs.
while garen and darius are worse than j4 (Who says otherwise is because he is a l0w el0 fr00b)you can't do nothing about fiora you should go tiamat black cleaver and after finish ravenous
The top lane Jarvan IV that's actually successful is the high damage assassin style build. He requires you to play very well though because you aren't building much in the way of defensive stats.
So you typically want to be running high damage builds instead of tankier builds. You'd want to look at a build like this 
boots of your choice, then the final item would be one of the following depending on what you need 
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If you're not against much in the way of bursty magic damage swap Maw out for Infinity Edge. His Q deals substantial base damage with an AD ratio of 120% of bonus AD, then his ult runs with 150% of bonus AD, it's just massive so it's almost wasteful to go primarily tank. Late game builds you can literally 1 shot squishy targets, and you have enough armor penetration to crush tanks between Last Whisper and the armor shred on Q.
He actually has a pretty high rate of success against Garen and Gangplank.
Well J4 recieved the armor buff, and in the future these strong champions will most likely get nerfed if they're still too good which will also buff him. J4 is waiting for a meta shift to reign as king again.
J4 is actually an assassin and should be built as such. I pref to play him full ad with maybe a randuins , it's funny cuz his ult can do 1k dmg and it's incredibly satisfying
