Fan backlash to a cancellation has convinced execs to renew a series here and there (but usually those were cases where the cancellation was on the fence anyway), but that's about it. There is no history to show a fandom whining about uniforms and alien designs "forcing" execs to change them. That said, I do think the complaints about the Discovery ship design did have an effect on the final design. But emotionally-driven angry ranting isn't what's going to get producers attention. Only constructive criticism, and feedback based in logical and rational points have any chance of getting heard and responded to.