Have seen the comment fields at Equestria Daily about the upcoming 3D series, which will be called the MYM series, and it seems that there was either high expectation pressure or dissatisfaction with the controversial aspects such as the issue with magic that dominate among the fans.
MYM Special #1 as expected revealed nothing but misunderstandings and rising resentment between the ponies who needed to get used to each other; what came as a surprise was the very destructive magic caused by the ponies’ discontent and loss of magic among the active magical ponies. The Unity Crystals suffered a PR disaster, and rightly so. Because the writers behind the plot had only shown half of the basis of existence for the Unity Crystals, as why the magic disappeared. The other half came in the IDW G5 #2 comic. Unfortunately, there was too long a wait between them, and far too many fans practice a narrow-minded distinction between different media, many firmly believed that the IDW comics are non-existent as part of the lore for the MLP.
The case with the Unity Crystals, which have now taken over the place after the Harmony Elements of G4, is due to a rewrite. The whole concept behind the Unity Crystals was taken from the first draft of the movie about a distant future or alternate world detached from G4, where the ponies were in a state of war with each other for a long time, with mistrust, violence and obvious contempt between the ponies who had painful memories in the way between them. This draft was discarded and replaced with a new one, but much of the rough work was done, as it was decided to create an enigmatic reality rather than a post-fallout reality. The magic must therefore go away, and to achieve this they chose to change some of the concept around the crystals so that the magic can be gone from the ponies’ world.
This leads to a new track for the writers who had to build up new lore that could explain why the magic disappeared, and “exonerate” the heroes from G4 for something that reminds too many of deprivation of liberty and irresponsible policy regarding the ponies. The mistake in MYM Special #1 was that only half of the explanation was shown - the very reason why the Unity Crystals exist, but this in the short term made it worse. We had to wait until IDW G5 #2 with the Discord Arc and the TYT ep. 18 to get more material on the subject, which thus makes it possible to put together the picture of the controversy surrounding the Unity Crystals. In-depth analysis and pondering had become necessary to see the contours of this.
Ironically, the G5 writers have used older lore to justify the Unity Crystals’ existence, which is to stop the magic of the ponies in certain scenarios, and that is by focusing on the emotional dimension of the magic. Everyone could see in the Special #1 that it was emotional instability that was the direct cause behind the disaster that nearly engulfed Maretime Bay. But there were signs that for the first time charted the magical world structure ever since the start of G4. We saw passive magic in the earth ponies. We saw emotional energy leaking from the ponies out to the Unity Crystals. We saw a rainbow of magic come out to the lighthouse as if a channel opened. We saw the magic in depth. And thus came the reality that active magic is separated from the physical world. Which explains why magic could disappear completely in a magical world, magic is layered. This idea of active magic dates back to S8, when Cozy Glow tried to remove the magic, by “sending” it to another dimension.
Many who criticize the Mane 6 for not solving the problem in their time, forgot something essential; passive magic and emotional power likely come directly from life energy - or the soul. This could not be touched, as it would concern the very essence of the Ponykind. This problem was never seen early according to Discord who was shocked despite his long life. One of the images about the upcoming series - which is not commented - shows a lantern with the earth pony crystal, which makes the IDW G5 #1 canon. Namely that a physical splitting of the Unity Crystals without loss of magic is possible.
The Unity Crystals have been fully explained by following all media - the movie, the MYM Special, the IDW comics and the TYT series. And that they will serve an important role for the G5. It has come out that the magic cannot disappear with the help of the Unity Crystals, and it happened during an apocalypse that saw the end of G4’s world.
It is very rare that lore in a fictional world arose immediately or is put in place, it is developed over time with the efforts of many who helped, several thousand people had worked on the world building ever since Faust began work on the upcoming G4 back then. The Unity Crystals are a very good example of this.