I'd be okay with a possible R rating if the plot touched on some of the darker, not entirely kid-friendly, aspects of Trek. Things involving some violence, death, assassination attempts, slavery, war, conflict and deep-seated hatred between certain species.
What I wouldn't want to see is a bunch of swearing and sex scenes that serve no real plot purpose but attempt to make it edgier and draw in young people that may otherwise not watch it because it is Trek.