My problem with MacArthur is that slavish obedience to unrighteous authority
And how would you define "slavish obedience" and "unrighteous authority". Is following the abortion laws of this country not "slavish obedience"? Wouldn't you say you are following unrighteous authority, unless you happen to believe in abortion.
And what is "unrighteous" authority? All authority is appointed by God. Our Lord Jesus told Pilate that he had no authority except that which is given to him by God. (John 19:10-11) What you are in fact saying is that you do NOT believe authority comes from God, that God appoints unrighteous governments, and reinterpret Romans 13 to suit your soteriology. (You've never explained about the taxing authority.) Fact is God raises up a number of "unrighteous" authorities to prove His people. (And yes, Ehud murder of the unrighteous king brought peace to Israel for eigthy years. Did murder make what he did right in the sight of God?)
I would say that MacArthur isn't the one who is preaching only half the Word.