You can beat DMC1/3/4 DMD with a fresh file save, no items and still get the highest end mission ranks. Precision controls is one of the reasons DMC games are so favored vs. most other action games. There is no "BS/artificial difficulty", enemies aren't randomly getting invincible frames outside of specific patterns or doing random damage. Dante never all of a sudden gets increased recovery frames and stunlocked because of it.
DMC 3/4 DMD's teaches you to balance your damage around enemies so you don't Devil Trigger them all at once and how to optimize your combos/damage output in doing so for quick mob clearing. The boss battles just reinforce your knowledge of their patterns which are all legit.
BS difficulty more along the lines of NGRazor's Edge Ultimate Ninja stuff.