It seems Discord's gonna be quite a cool villain after all. I didn't like the "chimera creature" theory, and thought he looks pretty pathetic when I saw the static screen at the beginning, but in the end it'll hopefully work. He looks like a complete goof, but depowers the Mane Cast in a second and doesn't even seem to think much of it. My favorite kind of villain.
Of course, it's a little girls' show and all, so he won't be
really threatening, but I keep my fingers crossed.
I don't think he's physically strong. His body looks frail, not to mention falling apart.

Also, I wonder, since de facto the Earth Ponies were unaffected by Discord, while he stripped the rest of the cast of their innate powers they were were using all their lives (well, except maybe Fluttershy who didn't like to fly), will that breed some resentment among the cast. Like "It's easier for you since you never had magic anyway, while I was ridden of my special talent". You know, since he's Discord.