We’re not done with the current movies
The modern films may not be everyone’s cup of coffee but the first two were successful and well-received for the most part. No one is going to say that Benedict Cumberbatch is on Ricardo Montalban’s level as Khan but does he need to be? The real villain of the film was Admiral Marcus and anytime you have RoboCop (Peter Weller) on screen, you’ve done something right.
Chris Pine, Zachary Quinto, and the rest of the crew have done great work (mostly) and a fourth film will only do more good for this franchise. It’s stepped in it for Star Trek: Beyond, but a fourth film with a different vision and new writers may be able to really squeeze the blood from this stone.
Yes, the passing of Anton Yelchin has hurt the ability to do a fourth film but the role doesn’t need to be recast, just bring in another classic Trek character to fill the void left by Pavel Chekov. That way fans aren’t disappointed at someone replacing Yelchin and you can explore new characters. That’s one idea, or you can bring in a character from one of the previous films like Alice Eve’s Carol Marcus or Sofia Boutella’s Jaylah.