I think you they should have an episode that explains why spike has no wings, and maybe possible will get them.
they should try doing a episode explaining how zecora got there, and is there more zebras, and where are they. So pretty much zecoras point of view and other stuff.
for season 7 or 8 you should make a new villan, maybe like a demon pony. This villan can make other ponys do what he/she wants. Maybe their would be a back story with this villan and luna. In flashbacks they would show that they were great friends, but luna pushed him/her away, and he/she didn't know why and got angry at that. In the flash backs it would also be awsome if luna's and celestias parents were in there, and that might have a connection of why luna pushed him/her away.
To get revenge on luna, he/she comes to equestria and destroys things to get attention. Once they figure out about the disaster they check it out, and luna has to explain what happens.