There was a G5 panel at Everfree Northwest!
Titled "MLP G5: The Lore, the Lies, and the Legacy", it serves to dispel misinformation regarding G5 and to clearly lay out how G5 was created and ended prematurely by Hasbro. It was compiled with the help of reliable sources in the fandom.
This post will only contain a bit of somewhat newer information that was shared. We highly suggest you read the panel's slide deck and Google doc for much more details. All the credit goes to everyone who worked on it.
Two major factors the panel pointed out that hurt G5 were CEO Chris Cocks and, brand manager at the time, Kat Maher-Smith. G5 was originally planned for an older audience but the target audience was soon changed to pre-school and elementary aged girls. This caused certain problems like G5 getting brushed aside as it was deemed "just for kids" all while focus shifted to G4 for its nostalgia factor.
As this occurred, many things were eventually cancelled, such as both G5 shows and even lots of toys. Boardtrot, Scout Kindheart, a Crystal Brighthouse playset, Opaline (possibly the one we saw at SDCC 2023 ), and Cutie Mark Club all didn't get released.
Pictured above and below are some mockups of presumably the Style of the Day toys from 2023. As you can see, new fully articulated bodies with joints were planned, but they were ultimately simplified in the final products.
Also speaking of Cutie Mark Club, as we already know, it was planned to be G5's Equestria Girls. Apparently it was supposed to get three seasons before it was cancelled according to the panel.
Again, we highly suggest reading the docs linked above if you'd like to read more about G5 in depth. Big thanks to everyone who worked on the panel.