For one thing, Nobodies aren't encountered until the last levels of the game, and are not actually encountered all that often unless you're specifically revisiting old areas you don't need to. They may populate several different places in the closing hours of the game, but you don't encounter too many of them if you're actually looking to progress through the final areas...and aren't getting lost. I remember only ever encountering like four or five tops from the Underworld's entrance to Mundus' throneroom.
Secondly, if your tactic is to keep using the same move over and over, then you're not gonna get any style points, because for as lenient as the system is with new modifiers, you still don't get jack for Style on the third repetition onward - of any move, while sitting around and waiting for a dreamrunner to 'port so you can perform this specific tactic pretty much ensures that your current Style grade has decayed to nothing, so if you got a C by doing that twice, congrats, you're going to be sitting at a C the entire rest of the fight if you keep doing that same thing - it's all a big floppy waste of time. And in a game series that is more about looking cool while killing enemies, rather than just killing them, why bother with such a boring tactic...? If you're just going through the game to get through it, sure fine whatever, but it's not conducive to what a Devil May Cry game is supposed to be played in the end. It's like how you can go through most of the enemies in all the games by just spamming Stinger if you want. It'll surely route a lot of enemies, but are you really having as much fun with the game by not tapping into any of the potential there? Not to mention that it doesn't work on everything, so you'll be up a particular creek without a paddle sooner or later.
Plus, trying to do a charged Eryx
combo on a dreamrunner doesn't work all that well, because after that first hit, they are in normal hitstun and will jump out at the first small window you take to charge. Hell, the
normal stygians on any difficulty above normal mode will block a combo string half the time if you try to do a pause combo like Death Coil.
I don't think you've done nearly as much research into these enemies man as you're trying to let on. It seems like you just heard about/did one thing that can be done and based all your assumptions around it :/
And a lot of the toughest enemies in DMC games become rather simple once you figure out the approach: Faust and Mephisto become completely unthreatening when you snatch/shotgun their cloaks off, Blitz is fairly easy to take out after dropping it's shield,
which is fairly easy itself if this tutorial is to be believed >.>