They brought many familiar faces from the previous generations in Friendship is Magic
, so the change in creative team doesn't prevent Discord's return. Worse, he's the one familiar face who could come back as himself rather than a new interpretation of the character, what with his powers and probable knowledge of the fourth wall.
And yeah, Discord's 'reformation' has always been a case of Luke & co. bringing Palpatine back from the dead, then looking the other way every time he genocides half a planet, because hey, it's only half a planet. It's only half as bad as what he could actually
Maybe that was one reason for this hypothetical war against Princess Twilight in G5's past? She's already thrown Equestria under the bus twice, first to save her friends
and then to save the mare who'd just conquered Canterlot and just said she'd gladly do the same to the rest of the world
, and after that she enabled the Bracchus Rex of their E-rated world for her entire reign. Not exactly a leader who can be trusted, is she? Even good guys would have reasons to want her gone.
To talk about something nicer, with this apparent focus on the different races of ponies, I hope we'll actually get to see
their cultures this time. We've learned a lot about griffons, hippogriffs, changelings and yaks, when their 'civilization' amounts to one glorified village each, but pegasus, unicorn or earth pony culture? I don't remember anything about them, other than Applejack's usual ego trip.
Crystal ponies got a little luckier, thankfully. I wonder if we'll see them again.