I appreciate what Roddenberry has done. He started the damn thing.
But as far as I am informed, quite a lot of what made Star Trek work and memorable came from other people, especially Gene L. Coon. The higher morales, the use of Kirk, Spock and McCoy as a trinity, the really good and memorable episodes really came from Coon.
Roddenberry himself seems to have not been a very good writer, but he loved to do unnecessary rewrites which apparently annoyed the other writers and producers (to put it mildly).
For example, I've heard D.C. Fontana's original script for "Encounter at Farpoint" was much better than the version filmed, which was rewritten by Roddenberry.
And I've read stories about what went on during pre-production of TMP, when he had to promise the studio heads not to rewrite the script before handing it to them, which he apparently did nonetheless.
Also, with TNG, I felt it was odd he didn't want to include any of the alien species from TOS. The Bolians were created for no other reason than a script asking for an Andorian and Roddenberry not wanting one, so they made him this new species instead. It seems they (Rick Berman and someone else who's name currently escapes me) practically had to smuggle the character of Worf past Roddenberry, because he was so much against using a Klingon on the show.
So I do appreciate that he created it. I actually am thankful for that. But I do not worship him.