I didn't really like playing as Nero in 4. I prefer having the multitudes of weapons, though I really only used Pandora's Box and Lucifer when I played as Dante, loved those weapons While Nero did have some fun game play with his demonic arm, i'd rather be able to choose the method in which I killed shit.
Though wailing a frail, old guy with the thing was incredibly entertaining XD
Who else if not Pinkie? You've already done Dante and i can't think of any other pony that breaks the fourth wall. Come to think of it Discord could also work. I don't know how far you've come into dmc 4 but as you may have noticed you fight the three "gatekeepers" in the opposite order as Dante and then you fight Agnus and the cutscene before the fight pretty much solidifies Pinkie and Discord as the competitors for the role
For me it's either the cutlass, fucking hated that tunnel where you first meet them, or the god damn Fausts, they ALWAYS hide in the fucking walls and never let you attack and when they do come out it's to "finger" you which takes way too much health of the bar. What makes it worse is that their AI is programmed to do that. The areas where i learned this is in that god forsaken blade-clockwork room, where you have to slow down time, and that damned elevator in the same freaking level!