Jarvan wasn't included with the bruisers that have gotten buffs lately. This guy was always a bruiser and has moved so far into assassin that it's legit hard to play him anymore. I'm the #17 or #18 mastery point holder in the world on this champion and in the last two weeks I can no longer even play him top lane and even jungle isn't really much fun.
Stop moving him into the assassin space and give him back his bruiser status. This champ should be an even match against Riven, Poppy, Aatrox, and Jax (though Jax technically does counter him I've always been able to outplay the stun in past. No longer possible). Hell he used to be good into Nasus but forget that atm.
His W Aegis shield needs to go back to flat scaling and he needs his base armor stats back. Also he has less health than many ADCs starting the game at this point, lower base stats than Jayce even and Jayce can be ranged. What are you thinking?
Stop running this character into the ground.