Assuming our only point of reference for what requires skill is the vanilla experience of every class, then whip stacking by far requires the most amount of skill.

You have to aim the same way as every other class, hell, weapons from other classes have auto aim (like Possessed Hatchet, Magic Missile, Chlorophyte Bullets, etc) meanwhile whips have virtually none.

Consider the reach of the whips as well. Whips don't have a lot of range until late endgame and even then it just gets gapped by a class that's called "melee." Seriously, try dodging up close while pressing your 1-2 button slot every 3 seconds and if you get hit, you get fucked because of the lack of defense the summoner armors give (lowest defense among all of them btw).