Strongly agree on the first but thought Marcus was (though underdeveloped) too much of a "moustache-twirler."
I always thought Khan from the Wrath of Khan was a bit of a"moustache-twirler." An over the top one dimensional bad guy. That really isn't a criticism just more of an observation. Hollywood has many examples of clear-cut, black and white good guys vs, bad guys and in TWOK Khan was a simple bad guy.
He was evil and even at times maniacal but I thought he also had significant pathos, notably "Admiral
Kirk never bothered to check on our progress" and the buried alive monologue.