J4 recieved a buff to his E spell that gave him more attack speed so he could jungle clear without loosing that much health and gank more often. The issue is that it helps his midgame a lot but his first clear is still terrible, you still need to go base when jugnlers like Zac, Graves, Reksai and the other meta junglers can keep clearing and ganking. The strenght of J4 are his great early ganks since he falls of late game unless you build full ofense, wich is harder in the jungle because you get less gold.
I feel that the change helped his midgame but riot needs to fix his first clear so he can compete with the meta junglers that get exp, gold and ganks while he needs to base to bu another jungle item component to not get extremely low clearing. Maybe make the E give him armor or extra AD against jungle monsters can help him solve that big issue.