Just my opinion. At times watching the gorn episode I felt like i was watching aliens. I had that feeling pretty quick when they entered that base. It was not hard to tell they were giving us an aliens story. The other examples like Balance of Terror I didn't feel like I was watching The Enemy Below regardless of the story.
A fair amount of Star Trek: First Contact is borrowed directly from Aliens. They don’t even try to hide it. It’s not the borrowing that matters. It’s how well something is borrowed.