Bixby, I hadn't made the connection between To Boldly Go and All Good Things--a great observation. STC's biggest problem is in it writing/storytelling, but then again, that is true for the vast majority of film. If there's going to be a stand-out issue, its likely the writing. That said, STC is, in my opinion, the best TOS-era fan film series in production values and acting, and, despite what I just said, in the writing too. Even Star Trek: New Voyages/Phase II pales in comparison to STC. Axanar has excellent production values, and is better written than STC, but it doesn't attempt to emulate the feel of TOS.
Here are some general observations about these fan films, first in how they vary from official episodes:
1. They are always derivative of official episodes, either as a sequels to the original episode or they use some aspect/character from a TOS episode. Perhaps it is in the DNA of these productions to do so--since they are already derivative by nature. This is a departure from the official cannon, which rarely referenced a previous episode. Once this pattern is noticed it quickly becomes annoying.
2. I also hate the references/homoges made to events/characters/terminology not found in TOS. It always sticks out like a sore thumb.
3. These fan films lack the subtlety of the original. They are way too preachy and overt, again, a problem with writing.
4. A big problem with the acting is that their portrayals often misses the mark. Kirk gives inappropriately nasty looks at the wrong times, leading you to think there is some underlying problem where there is none. Say what you will about Shatner, he was always on-point and hit the right tone consistently. A tough act to follow.
5. The constant questioning of orders/second guessing a superior officer in fan films is beyond annoying. The supporting cast have way too many opinions (in my opinion). Agree with it or not, Vic needed to be more of a Shatner when it came to cutting or taking lines given to the secondary characters. It this is any example of how TOS could have been, Shatner made the right call in insisting on streamlining the scripts to feature the lead actors (mainly himself).
Like you, I could go on and on, but here are a few things that these fan films have helped me to realize:
1. Just how incredibly talented and professional the cast and crew of TOS were. Top industry professionals. Period. They were able to produce a superior show on a weekly basis, within the limitations of 60s network television, than these fan films can manage with 6 months to a year to produce a single episode.
2. They demonstrate how without a network, sponsors, and the general public to keep tuned in, an episode can become a tedious, confusing, and convoluted mess.
3. My final observation is STC specific. It is not the same type of show that TOS was. TOS was by-in-large an action adventure with dramatic undertones. It also ventured into other genres like horror, fantasy, and comedy too. STC is by-in-large a melodrama with some elements of action-adventure. One big reason for the difference is likely financial. An action adventure story is likely much more expensive to produce than a drama, so that's understandable when you're producing episodes out of your own pocket. But even the more dramatic episodes of TOS were much more engaging that these fan films.
I've ripped on them enough. I hope the big takeaway is the appreciation these fan films produce in me for the actual article.