Cute

@Background Pony #BCAD
 
I still like the OC. It’s like a seasoned musician trying to explain to a non-musician why a certain performance was bad: as an artist (or at least one who spends a lot of time studying art), you’re used to recognize mistakes, inaccuracies. To the untrained ear (eye, in this case), nothing seems wrong. And I’m untrained as it can be. Besides, color palette isn’t what makes an OC. Determining that it’s bad based on color choice is silly.
 
And don’t call me Shirley.

@And Brother I Hurt People  
Shirley, you can’t be serious.
 
Look at that appalling asymmetry between the mane and tail! The mane only goes from red to green, while the tail runs across the whole spectrum. That alone is enough to throw off any semblance of balance this design might have ever had.
 
Besides that, the gray eyes are dull, and the freckle placement makes her look like she just had a bad carwash.
 
Splitting focus between a bold, high-saturation acentric range of hues and hueless eyes, coat, and freckles would never be a good move in any context where a unified design was desired. The emphasis on dark and neutral colors along with the cacophony of bold colors used in the mane and tail are completely dissonant with the aesthetics of My Little Pony, and to top it all off, the CM looks like a copy of Rainbow Dash’s.
 
There is no way that you could convince me that this is a good OC.

Maybe it’s just the way her hair is styled, but black and rainbow actually work for this OC.