It's a bit of a pet peeve of mine but "magical pegasi" make me annoyed in the sense of not being able to fly if they're not powered up by magic. I know that was a thing in G4 too but... it's not like their wings disappear. They're just kind of winged horsies they don't need to have an extra magic spark to fly. Also they kind of forgot that earth ponies have a sort of subtle invisible magic almost giving them a connection to the land, which the world of G5 being more industrialized than G4 Equestria makes me wonder if they could have retconned it somewhat in order to give earth ponies a sort of folk magic. If the G4 unicorns have magic down to  a science, the pegasi need magic to fly, the earth ponies should have a little bit of fun magic too.

I was going to write a whole thousand word ramble about the connections with G4 but I've just summed up my questions I hope are answered in bulletpoints instead. I really like the fantasy world elements of G4 a whole lot and I'd hope they carry over to G5. Though because they're keeping G5 set in Equestria:

-How old was the Zephyr Heights station Zipp shows Sunny and Izzy? The Wonderbolt poster and the posters advertising the various settlements didn't look extremely old which makes me wonder, has it been closer to 100 years or 1000 years since Twilight becomes the ruler of Equestria?

-How long was Twilight's reign? Is the sudden segregation of the pony species related to her somehow? She doesn't seem to be around anymore, so did she disappear or did she pass away somehow?

-Are Celestia and Luna remembered in any capacity outside of history buffs? Argyle seems to have a couple old murals of them around and Sunny has Celestia's cutie mark hanging in her room. Do they just remember that once upon a time there was a pony who lived for more than a thousand years and controlled the sun (also her sister) but they're just kind of gone now? I feel like that's a potentially terrifying concept for the ponies of G5

-What happened to Princess Cadence, Flurry Heart, and the Crystal Ponies? I suppose the Crystal Empire would be isolated given it's surrounded by a looooot of snow but that makes me wonder if the Crystal Ponies, Cadance and Flurry Heart are still kicking around up there separated from the rest of Equestria.

-Is the Tree of Harmony still around? If so, is it still increasingly and scarily sentient? Towards the end of G4 it kind of develops sentience and begins projecting itself as Twilight and forcing some random kids to do a life-or-death trial in order to figure out if "friendship is in their nature", but I wonder if that could have been the origin of the unicorn/earth pony/pegasi crystals that are apparently required to spontaneously create an alicorn and release magic back into the land. I kind of wish the crystals were symbolic rather than actual magical mcguffins though tbh.

-Where did the other magical creature species around Equestria go? The end of G4 has griffons, yaks, hippogriffs, dragons, and changelings becoming integrated into pony society and it suggests that's going to be a continuing trend, but they're gone by G5. Ultimately I understand the series is pony-based thereby all the main characters should be ponies, but from an inuniverse perspective and it makes sense for them to be the first to go if pony society was segregating itself for whatever reason. I guess it'd just be interesting to see where they went? I guess the changelings could still be around