your arguments are always terrible, KK. i think you just argue with what you think the matchup would be like, without any substance because of a lack of experience or actual knowledge on the subject. you'd be mad cool if you didn't, too.
you think sheik ***** marth like 70+% anyway, so what's the difference in me saying you're playing crappy marths if you're destroying them, than you saying i'm playing crappy marth's if i even get to nair them with ness. lol terribad logic. not to mention i play with legit one of the best peach players period...who also has a dag nasty fox (traded games with m2k and almost beat jman in dittos at apex). but...i guess he sucks, despite performing better than anyone in your crew. moving on to the actual points:
most every dash attack can be CC'd to a decent percentage. it's not just ness's. and marth isn't actually amazing OOS. due to the forward distance that can be gained by a DJC aerial, ness actually has no problem with marth waiting in shield and trying to attack out of it. there's a video of it somewhere, i don't feel like fishing through old ness boards to find it, but the hitbox on an l-cancelled low-starting DJC fair is amazing. it hits until you land, and doesn't have much lag, allowing ness to grab right afterward. i mean, it's not completely safe, marth can grab first if he times it amaingly, but he can do the same on a falco pillar and how often do you see that work? also, DJC bair shield pokes like crazy, marth can't shield camp ness.
marth should also not intimidate a ness from above. ness's double jump is crazy weird in how is speeds up and slows down, and it's really hard for a marth to follow and try to intercept with a dair or even a fair. ness's ground speed is also redank, he can wavedash/dash dance camp as well as marth.
even with all this it's obviously not a close matchup. you're right about his grab not being even close to marth's grab, and ness can't combo off of it, but the same applies to peach. honestly the most terrifying things about marth to me are his spaced retreating/approaching nairs (not as bad when being spammed in place, obviously), his dtilt as both a shield poke and edgeguard, and his utilt once he gets ness above him with a grab/dash attack/fair.
the matchup is terrible for ness. i was just saying it isn't as bad as peach. meaning ness actually has a decent chance on a stage where he can find the ground and have room to recover (pretty much most places except marth's story and FD). and find me someone who would know better, please. most of ness's matchups are closer than he gets credit for. this is obviously due to no one good has played ness since simna. these charts assume that the 2 players are of equal skill, so i think everyone can throw their previous knowledge of watching random to good marths pummel the crap out of random to mediocre nesses out the window.
also, why the crap are we talking about ness? should we debate high and top tiers like every other thread ever? lol.