Please continue reading.
Though, I've been thinking of alternative ways to tell this story. I had this idea rattling around in my head for a while. However, what put me over the edge was reading Harry Turtledove's The Misplaced Legion. I would love to dive more into the cultures of Terra, particularly the harpies to establish them more as a people as well as an adversary. Also, maybe get more G1 lore in. Like the origin of the Twinkle Eyed ponies and develop that story and the Jewel Wizard more.
Also, maybe develop a pony culture other than Equestria's. I know it provides a familiar base for readers, but that world is so broken to want any association with it.