I love it and hate it.
Love it since it's one of the best ever Trek episodes.
Hate it, since it destroyed the Roddenberry vision.
People who criticise the Roddenberry vision frankly miss the point, and essentially the point of art (a TV show, especially a dramatic one, is still art by definition). No art form must absolutely correlate with reality, and to suggest as such is silly. I doubt the Great Bird, who was seemingly an intelligent man, believed his vision was reality. It is essentially a hope for the future, and to be taken in that context alone.
To suggest all art forms must correlate with reality means if one reads a Superman comic or movie, it should be dismissed. Aliens from distant worlds who get superpowers from the Earth's sun? Even though Superman highlights some realistic phenomenon such as nobility, kindness, heroism and dedication, no Superman is crap since aliens who have freeze breath don't exist in the real world!
Sometimes an art form should be seen for what it is, since art is by definition an abstraction. I personally don't care if the Roddenberry vision is "unrealistic", that as aforecited misses the point. It is an abstract vision of how humans could be in the future. One of the major appeals of art, frankly in all cultures, is that it allows great imagination. People who say "it's not realistic!" well maybe they're autistic or something, they lack the capability to ponder non-concrete concepts.