Jarvan will never be good
Extremely weak in 1 on 1 fights, and an even worse champ in big teamfights
When J4 was originally released, his E gave him ARMOR and attackspeed which gave him insane dueling power.
Please buff his E, as of now he burns two skills to just run in and feed, then blocks his teammates in so Jinx and other champs that play off of kill resets proceed to ace his team.
You would have better luck playing Wukong honestly, does the same exact thing except he's.. Superior in 1v1 fights AND teamfights