Trek does need to avoid character like Token...sorry I mean Travis Mayweather, who really was there to tick the diversity box.
That's really not fair. If you watch the first season, you see that Travis gets plenty to do and is given a good amount of character development. As conceived, he was an important part of the 22nd-century worldbuilding -- the "Space Boomer," the embodiment of the early generation of space pioneers who were now being displaced by faster starships. He was also a natural raconteur, a teller of ghost stories and practical joker, and he was a history geek who really embodied the enthusiasm for exploration that drove the cast in the first two seasons. He got more development in the first two dozen episodes than Sulu or Uhura got in three seasons and six movies.
It was only after the first season that he began to be marginalized. I think it's because he gave a disappointing performance in the climax of "Fortunate Son," his big focus episode that season, so afterward the writers started downplaying him. It's true that in seasons 2-4 he did tend to be relegated to the background. But given his greater prominence in season 1, it is clearly wrong to assume he was intended
as merely a token character from the start.