Jarvan needs Jungle Specific Changes, not direct buffs
Jarvan Top Lane is currently sitting at a rather high 52.4% Winrate, but there are still buffs to his E attack speed on the PBE according to Surrender@20.
If Riot keeps trying to get Jarvan back into the Jungle with constant buffs, they may make his top lane too strong.
In the end, I think Jarvan's clearing is the problem with J4's Jungling, so if you can buff that and that only he could be a strong top Laner and Jungler without being broken (kind of like how Gragas is right now)