Yes, I agree. The aggregate of features of an Andorian is probably unique, but perhaps only if the name Andorian and the backstory of their particular planet is attached. I doubt Trek was initially built with a large copyright compliance effort, and there could be substantial barn doors waiting to be found now that prior art is so much easier to research. If I were owner of an IP firm with lots of mad money to spend, and I really wanted to pry trek away from CBS, I might threaten to make good on such research unless I could see space made for fan films. Will watch with bemusement as this analysis is retconned into the Axanar story.
Wouldn't it really be moot with something as old as Star Trek? You may be able to find a blue alien with antenna in the way back machine. But either the copyright would've lapsed due to time or the fact no one has used or defended it for more than a half century.