I can't really detect a flaw, or basically something in my opinion that I do not like.. but I don't technically find this original. I've seen many pony arts with the exact same concept, technique, etc etc...
I do enjoy the vision. I love how you make it look similar to the actual art style of animation in the actual show, yet with somewhat your own uniqueness and taste. I do love that in a artist.
I do believe Pinkie needs to put on some pants though, hehe. But besides that, everything is amazing.
Also the lil pony plushie she has. I love it how you have darker lines on it to represent the sewn parts of the plush.