Very good! You've really got the silhouette down, and he's rigged very well!
You shouldn't limit yourself on the texture though. Discord does have mostly flat colors on him, but there are still areas you can really accentuate his forms.
I think you should take the model into a sculpting app like sculptris or mudbox and make him a normal map, and maybe add some extra details in the diffuse.
Here's one I started a while back:
It's not the greatest example, but I'm sure you get what I mean. I tried to add some hints of muscle to his legs there with the normal map, but even then I could have done a lot more, especially with the arms.
Still though, not everyone wants a weird mix of ponies and realism, so there's nothing wrong with the way you have him now, although I'd probably give extra detail to the bat wing and paint some nostrils and feathers on there.
Can't wait to see more from you!~