There are tons of minutes between league, domestic cups and UCL. And Klopp is one of the few big club coaches that places a lot of emphasis on training.

It's either time for him to make the jump to a big club or he would have to commit a couple years to a mid table kind of team.

Unfortunately, the instability at Dortmund probably hinders his development as much as anything.

All that being said, if he needs practice preparing for USMNT, he should go to the Championship. That way his supporting cast would be closer to what he'd have to play with!