If I was gonna predict what's gonna happen in Part 2, I'd go with...
Prediction 1 - It turns out Discord is actually a servant of Celestia and the whole thing was set up to test Twilight Sparkle.
Prediction 2 - It's all just a dream.
Prediction 3 - Twilight, having lost all her friends, decides to start getting cozy with Discord. But then she becomes determined to beat him again when she finds out he's been cheating on her with Pinkie Pie!
Prediction 4 - Twilight
almost gives up, but then changes her mind because... let's just say it ends up becoming a Twilight/Pinkie clopfic.
Prediction 5 - Spike finds out about what happened and takes his rightful place as "most competent character in all of ponydom" (possibly with a little help from Owlolicious) to pick up where the girls left off. Since there's no possible way to corrupt Spike, Discord loses.
Prediction 6 - Luna saves them all by making a terrible sacrifice and once again accepting the power of Nightmare Moon, the one force that Discord can not defeat for the night has been around longer than harmony and discord have. (Maybe not, but personally even though I don't like the "villain" episodes I honestly thought Nightmare Moon was a lot more interesting than Discord).
Prediction 7 - In a shocking reveal, the show gets canceled before the next episode can air.
Those are my (half baked, tongue-in-cheek) predictions!