I would like to point out that Exeter is not the only fan film that has been started and then not finished for many years. Star Trek: Counterworlds also falls into that group, as does a film about Sulu, Yorktown II. (Both of these still intend to complete them, and Yorktown II has been open for over 20 years!) Star Trek Roddenbury created Part I of II, and never did the Part II. Part I was released about the same time as Exeter's first episode. Star Trek: The Way Back took a break of about a year, after releasing three of nine parts. Finally, Star Trek Phoenix appears to be relenting from their position, but after much ballyhooing about how professional their fan film would be, they then said they would not complete it (yes, it was Part I of II, not acts I through III of IV).
I include Phoenix because it was also a high-quality film, even though I classify it as a pitch for a professional pilot.
A simple majority of would-be fan filmmakers never complete any films.
My only quarrel with Exeter is that their website is misleading to a newbie who does not know their second film is incomplete. This could be fixed by adding a single sentance to the download page.
Clearly the best solution is to watch fan films not by going to each individual website but (here comes the pitch... watch several people hurl garbage at me ... pardon me as I duck...) at Star Trek Reviewed! http://startrekreviewed.blogspot.com/
. Links to over 400 completed Star Trek fan films, and over 200 Star Trek audio episodes, and reviews of any of these that I could locate. That's a lot of Fan Trek! In addition, I have links to other indexes of Fan productions, including one for Music Videos, several for Star Trek games, and dozens for Fan fiction.
If, like me, you've seen all the Pro Trek, there is a lot more fan Trek out there than Exeter. Just to make him REALLY MAD (Randy Landers is a great editor and a great filmmaker but let's just say he's going to hate this post) if you only want Star Trek Fan productions based on the TOS era, you can look at Orion Press! http://www.fastcopyinc.com/orionpress/
a much more professional website than mine! (Pardon me now, while I find a rock to hide under...)