Tokenism is just a fancy way of saying, "I think that people that have traditionally been underrepresented need to clear a higher bar to have the same representation as white hetero men." And when you put it like that, instead of saying "token," it not only becomes more clear, it becomes much more distasteful.
I mean, that's one way of putting it, sure, but that's not the argument being made.
The argument being made, whether we agree with it or not, is that if a minority character is enjoyed by the audience, the tokenism point will be ineffective.
In the end it's a slightly irrelevant argument either, I would argue, because it's a symptom not a cause. It doesn't really matter if a character is called a "token" or called "boring", because it represents the same thing.
The audience didn't like them. It's just that if they're a minority character, some people (usually white men) rationalize their dislike with words like "token", and whilst that's perhaps unhelpful, again, it's a symptom, not a cause.
I don't think being a minority is as much of a bar to the audience liking them as
@Paul Farquhar seems to be, by the way. Like, let's look a situation where Michael is white, and otherwise everything is identical. Would people like the character more? I don't think so.
So you could say "All you're arguing is misogyny is stronger than racism", okay what we made Michael a white man, and gender-flipped Ash and so on? Would people like the character then? No. I still don't think so. But what would change is people would call the character "boring" more and "token" wouldn't come up.
So I would say what this really comes down to, once we swish away the smokescreen caused by tokenism arguments, is that certain characters don't connect will with the audience, and that this is largely unrelated to their minority status or lack thereof. You can see this very easily with all sorts of minority characters who do connect with audiences including ones far more conservative than that of VOY. You also don't see more people liking, say, Adira when an audience is less conservative. But their terminology/rationalizations for why they don't connect with the character might change.