I honestly don’t think anyone is going to agree on the Ness argument and he seems like the most polarizing character in the meta right now. At this point we’re rehashing the same points in different ways. It’s ok for everyone to have their individual opinion on the character but right now his results and kit show a high tier. Yes he has weaknesses. Yes he could drop but so can any character. I think we should just put this to rest for now and revisit it in a couple months
I think its very clear what the problem is and it's that people are utilizing too much "impression" of a character, especially outside of the context of Ultimate without expressing what the results actually are. In other words, people have formed an opinon that directly contrast with the results thus shown. Sometimes you need to form an impression especially if there's no results to back it up. But that impression should be used to prove your point, to show the results of your opinion.
As an example, will take

as an example. Plant is such a new character with so little results under him, that the only thing we can do is make an impression. Some say his specials provide an excellent way of spacing, mixing and edgeguarding. Others claim his poor neutral game and recovery hurts him way too much to be good. He's got a few tournament results, even a win in one case but one could just as easily claim this is due to a lack of knowledge on Plant. As time goes on, we will get more results about Plant and have a firmer idea of where to put him. Don't have much of a choice but make an impression and the idea is we'll use that impression to prove whether we are right or wrong.

is another character we can do such a thing with, in this case his recovery. There used to be two impressions, one was that his recovery was much better than in Smash4, gave him multiple options and some even declared him a good character now. The other side of course said that, even if it might have been technically better, it was still heavily flawed and it wasn't going to help him much, if at all. You had two different impressions but one of them, the "Little Mac sucks off stage" crowd was right. Because they had the results to back up their claim. By the end of the day, it was proven that Little Mac still suffered from the same thing he did before.
We all got to start out with some kind of impression, especially when there's not enough results to back up a claim. However when a character has nearly 100+ placements and over 25+ first places spread out across several tournaments, people, places and months. Results that match up with other acclaimed "High Tier" characters and someone's going to say...
"He's probably only Mid Tier..."
Much less the "garbage" some players have indicated and I go look at this child with all these results and I'm just going to look at the person in question and say...
"What the heck are you talking about?"
Here's the thing, if someone believes Ness might fall because they believe people will be able to exploit his weakness more, that's fine. However, that's a future thought and requires results of some sort to back up. Right now, with what he's shown, Ness is a high tier character and he's not going to stop being one because of what people "think" he might be in the future. He'll stop being one when people prove it and show that their results are right.
I will repeat the exact same thing from my earlier post. Based upon Ness's current results, if he really is only Mid Tier, much less worse than it means either two things.
1.) People are wrong and Ness really is as good as his results claim.
2.) People are bad and have yet to find a way around this apparently simple character.