The major part of this episode consists in it being another "theme" based holodeck story; with the common malfunction aspect thrown in for good measure. While a lot of how you view this episode will depend on whether you are a fan of these types of adventures to begin with, the episode actually poses some thought provoking questions to the viewer considering the exisential status of holo-created entities and the possibility of their evolution; partiucalairly the potentiality of them developing self-consciousness/awareness and the ramifications that develop from this new form of existence.
Does the fact that Moriarity becomes aware that there is more to his daily surroundings or reality require us to confirm this or to contribute to his knowledge since he made the initial bound himself. Keep in mind that trying to see beyond the surface is a trait that is characteristically human and a trait of our intelligence or mental processess. We recognize that there is more beyond simply what our senses provide to us, and science has strived since it's creation to try and illuminate what stays dark and hidden to our limited senses. Does the fact that Moriarity now possesses self-awareness void our right to end his program; essentially is shutting him down now the equivalent of the "murder" of sentient being? These are just two issues that can be examined through this episode and they play a big part in elevating this story beyond just the average.
Although all of these existential changes and subsequent questions occur through an unintential command issued by La Forge, a lot of them become the standard and are purposely programmed or developed in holo-creations in the Star Trek universe. The main one that comes to mind is the Doctor in ST: Voyager. In the Doctor we get a holo-creation that not only recognizes that he is a creation in a larger or different reality, but also a character that is able to interact with this reality through the use of the ship computer and is ultimately able to start and end his own existence at whim.