I honestly don't think Pep would do well in MLS. Much of his success comes on the back of a basically unlimited transfer budget, and I don't think he'd make it more than 20 seconds into an explanation about the difference between GAM and TAM before his eyes glazed over:

It would also go some way towards answering another question often sent the way of Guardiola: what could he do with more limited resources? While there is increasing flexibility, a salary cap restricts the wage bill outside the league’s designated players such as Messi and another former Guardiola student, Thomas Müller. There are no limitations on what a franchise can spend on staff, though, opening the door for an ambitious owner to make a move.

If he wants a new challenge try a fourth division club with no money in Sao Paulo or something.