During Smashes I'll regularly get n-airs instead of f-airs of d-airs.. Though when I go into Training, I don't get a n-air once. This is with the C-stick set to tilts (which I wouldn't have if Smash C-stick kept aerial momentum). Almost makes you think Nintendo went out of their way to gimp the C-stick instead of these being bugs.
Keeping my fingers crossed this will get fixed soon, because it really is quite annoying.
EDIT: I've got it! When you C-stick 'between' the other aerials, you'll do a neutral air!
Here's what I mean:
Not very practical if you ask me though.