There are lots of mediocre to bad actors out there with long filmographies. This isn't a measure of acting skill.
My point here is simple. The character had a lot of potential, but that was left unrealized at least somewhat because of the way the actor portrayed the character. I've seen Philips in other parts, and he brought the exact same qualities to those other parts, that is "annoying". It isn't hard to do the math. Perhaps he has a long filmography because he is the first actor a casting director thinks of when they need someone confused, weak, and annoying for a part.
You don't need to get personal everything someone strongly disagrees with you. There is controversy around this character, when the character should have been really interesting, and I blame the actor.
And the performances you listed are not what I'd consider great performances. They were adequate performances at best, and perhaps could have been great with better actor.
Now, are you going reply how great he is again? Funny thing is... anyone could have been cast for this role, and right or wrong, you'd be having the exact same conversation with me. They could have cast Billy Barty to don some makeup and hobble around as Neelix, and you'd be telling me exactly the same things here.
Think out of the box a little.
Edit: Bad acting: Do you remember that horrible, limp performance by that original Captain Janeway? Thank God they recast her at the last minute. After watching that performance, and listening to the "official" reason why she left, it occurs to me that one would have to have oatmeal for brains to believe it.