I think the writers have a chance to create something very different. Some people didn't like the leaked concept art, but, is that something bad? Is it bad that the writers are going to create a new My Little Pony TV show with different details so the show is going to do its own thing? It's not like you present the changelings in season 2 of Friendship is Magic and you destroy the concept of the changelings four years later as I complain about the ending of season 6.
If the G5 is fun, solid, exciting, creative and inventive, I will be thrilled.
I have a couple of wishes right now for this version:
-The main characters should be recognizable and they shouldn't be dived into parody mode in the next seasons.
-They have to use a different animation tool. Adobe Flash is pretty dated right now, but the movie shows that Toon Boom Harmony would be pretty great to recreate these beautiful art designs. It doesn't have to look exactly like the movie, it can be like the Tangled show or like Steven Universe or Samurai Jack.
-New and different creatures in new and different kingdoms/cities/towns/forests. Zebras, lions, dragons… The designers have proved with episodes like Gauntlet of Fire that they can be very creative in the art design.
-The episodes have to be 11 minutes instead of 22. You could argue that there will be stories that will be better if they are told in 22 minutes, but Friendship is Magic has many episodes that didn't need to be that long. 28 pranks later, Buckball season, The one where Pinkie Pie knows, Flutter Brutter… So, if they have to create a long show, I think the episodes should be shorter to avoid the filler problem.
Most importantly, the show has to be fun, simple as that.
The writers and the designers have a lot of time to polish everything for 2020, so I'm patient.