i'm convinced that the bayo ness mu will develop much like the bayo luigi mu, in the sense that when bayos learn how to play a defensive neutral properly against ness, abusing his linear approach options, and abuse his poor recovery/disadvantage state, people won't question that bayo has an advantage in that matchup. i'm positive bayo wins that mu, though not by much. almost every top bayo matchup chart says she has a slight advantage, and the ness players seem split between even and slight disadvantage. it's an interesting matchup because ness can tack on damage really fast, and actually has a semi-relevant advantage state against bayo as well as oos options to counteract some of her typical pressure. although ness isn't packing tons of rage, his moves have the advantage of trading and often winning if bayo misuses or overextends with an aerial option. ness also has back throw to punish laggy special landings, a very consistent punish option that leads to kills at high percent. witch time is generally not that good against ness because he has hard punishes for witch time, limiting one of bayo's more absurd tools.
still, there's a few major points that people don't seem to understand about the matchup. for one, bayonetta wins neutral, a fact some people here really don't seem to get. ness doesn't have good approach options to counteract a bayo playing around his limited options efficiently, and he's not really going to keep bayo out either. someone mentioned retreating fair - this option can certainly be whiff punished, and is far from an efficient answer unless the bayonetta player is just haphazardly spamming back air (which many mid/high level bayos do, so i'm not surprised that people would think this is what bayo neutral is). it's typically not difficult for bayo to wait and react to ness's option, and there tends to be little risk if she anticipates the wrong option or whiffs her punish. this is a mu where, if the bayo player wants to, they can literally just not get hit for extended periods of time without too much the ness can do about it.
bayonetta has a perhaps even more relevant advantage state because edgeguards will (or at least should) frequently lead to death if the bayo player executes properly. ness's disadvantage in general is notably worse than bayo's, as there's a difference between adding damage with pkt and killing off traps on typical landing options.
P
Pyrover
mentioned that ness is not very susceptible to ko combos off the top, and i have to say that i just don't see it. ness isn't much more or less susceptible to bayo ladder combos than the average character. i think ness's grab may also be overrated in this matchup, and grabs in general, because bayonetta is very capable of playing anti-grab.
at civil war, 9b beat fow 3-1 without doing half of what i said. he landed a pretty lucky edgeguard stock 1 of game 1 and then did not go for any optimized edgeguards all set until the last stock of game 4. in this set, he won 2/3 games on smashville, ness's best stage by far. he basically won by playing fundamental patient bayo, waiting out fow's approach options and punishing accordingly. he didn't even really camp except for one part of the game in game 4; he just played a patient neutral. since people here care about results, i also decided to investigate other examples of bayo vs ness at top level (salem has no relevant sets against ness, which is why he isn't mentioned).
- captain zack lost a set against fow at zero saga last year, and won a set against great gonzales at royal flush.
- 9b, in addition to his set against fow, played a set against taranito in august of last year, which he lost, as well as a set against masa that he won.
- ikep has played 2 sets against taranito and a set each against masa and gakuto, all of which he has won.
- jk has traded sets with fow (might be negative overall, i didn't endeavor to check every bracket) and won most of his sets against bestness, additionally defeating shaky last weekend. he has also lost a set to nakat's ness.
- nakat has set wins over saj and jk, as well as a set loss against saj
- great gonzales has a set win over pink fresh
just pointing out that the results of this matchup are mixed, probably a slight edge on the part of bayo, though there's limited data from which to draw these conclusions.