And about Discord's fate, would you rather haved Discord turned into cutesy pony that says two lines and disappears to the next season? But more seriosly, unlike NMM, Discord's state was probably unchangeable.
Perhaps, but I still think it could've been handled better. I'm reminded of an old RPG, Faery Tale Adventure 2. Ostensibly, you're on a quest to defeat Chaos (who is personified as an actual flesh and blood guy), but if you do that, then Order wins and encases the universe in perfectly organized but totally lifeless crystal. If you let Chaos win, the world is also destroyed, because the laws of physics no longer apply. The way to actually win the game is to bring the two into balance. I find very much the same thing could've been done in the show (and very much the same aesop dropped as well), but unfortunately that opportunity was missed.
I also get even stronger totalitarian vibes from Celestia this time around. She ruthlessly disposes of her anarchist rival so that she can impose strict order (and like a true villainous mastermind she does so using pawns, without getting her own hands dirty!). And then in the latest episode she's perfectly fine with letting everyone think she was going to actually punish Twilight. She doesn't go "oh I wouldn't punish her for that". Oh no, she goes "I'll
let it slide, but all you lot will have to work it off". She doesn't seem to mind that the ponies are absolutely terrified of her, in fact she seems quite chuffed. And let's not forget, shall we, that it's only Twilight who's had any real contact with her and knows her. And she's by far the most scared of her. I think that tells us something.