Well, obviously going with The Man Trap as the series opener was a huge mistake. Look how it put Star Trek in a hole that it has never come out of.
Sigh. You know I didn't mean it made people consider Star Trek a kiddie show FOREVER.
But what Man Trap did do was show the critics the highly touted new SF TV series was just another monster rally with a high body count and a grim cast. Instead of it being considered a winner right out of the gate, it was considered a reject from "the kidvid bloc." Check out the national reviews if you don't believe me. It's all about first impressions
WNMHGB was a better episode to kick off the series, as it aimed higher, had better procution values and had more layered and dimensional performances. As such, it might have been better appreciated in the press and got more people to check it out.