Trek improved twice when Roddenberry took a step back. First, it was the movies after The Motion Picture, and then it was TNG after season 2.
He set things up nicely, but the restrictions hurt its future. Once writers could write without Roddenberry's "box", the show was better able to connect with the audience.
My favorite Trek is DS9, which is just about as anti-Roddenberry as you can get.
Also when Gene Coon came in during the first season of Trek, he added a lot of depth to the characters and the universe.
Roddenberry set up the framework, and others filled in the gaps.