Jax is Problematic Because of the Availability of Health + Damage Items

Old Jax builds were essentially:

Trinity Force for damage, followed by tank items with good HP values.

Current Jax Build:

Now Jax gets a similar amount of HP, but with a much higher damage potential, and a shield, at the cost of lower resistances. But thanks to Conquerer and his ultimate, the lower amount of resistances is rather negligible.

Maybe it's time to look at the defensive stats he gets from his ultimate, particularly the magic resist.