Whatever you might think of the WTO, a unilateral pullout and imposition if broad tariifs would be the worst shock to global markets since the wall Street crash. I'm starting to think Trump is actually a Marxist plant who wants to dismantle capitalism.
Let him saber rattle on the WTO to get better deals and/or to replace multilateral deals with bilateral deals where the US has more leverage.
As far as the EU goes, Trump is right. It was, in part, created as a one-Europe government to counter the United States.