What bad experiences of Gary Lockwood and Nicholas Meyer do you mean? For the former, do you mean his girlfriend telling him Roddenberry tried to kiss her? I know Meyer didn't agree with all of Roddenberry's script notes and surely was unhappy with him leaking Spock's death.
I'm never going to defend his shitty behavior, but I am going to defend him a bit in his role on TOS, where it seems to be in vogue to assign credit to other people for stuff he did. I've read a lot of the behind-the-scenes paperwork and it's clear that he was the one who most understood the show and made suggestions to get the scripts in shape and keep the action quotient up to keep NBC happy.
This is all OT of course.