I remember thinking the Salt Vampire was scary and the transporters were cool, but that's about all I recall. I certainly wasn't analyzing the show in a critical fashion when I was seven!
To add a bit of historical context, however, nobody back in 1966 worried about shows being too "Monster of the Week." That wasn't even a term back them. Nobody expected ongoing story arcs or character development on network shows, let alone sci-fi adventure shows. Heck, "The Outer Limits" was literally a Monster-of-the-Week show and "The Twilight Zone" was an anthology series.
You can't really apply 2014 expectations and standards to a 1960s TV show. It's like wondering why a black-and-white Fred Astaire musical doesn't have more rap music.