Impossible question. Different genres require and test different skills. The skill required to play Mushihimesama Futari and not die every three seconds is not the same as the skill required to win World War 2 with France in Hearts of Iron.
And because those skills are so radically different, saying that one particular genre requires more skill than another is impossible. You can compare within genres which game requires more skill, because the skills being tested are largely the same, but not between genres.
And because those skills are so radically different, saying that one particular genre requires more skill than another is impossible. You can compare within genres which game requires more skill, because the skills being tested are largely the same, but not between genres.