I did a pretty thorough study of Cadence. She is very strangely proportioned... and not consistently proportioned throughout the episode... She has Luna's sizing for her head and limbs, but is smaller than luna...
It does come off a little weird in pencil sketch
I may shrink her head a bit when I do this in digital... other than that, and adjusting the hind legs a bit, I think this will look good.
Her proportions are weird, and tend to change a bit during the show. the only ideas I can think of is to put less roundness on her forehead(like slant it a little) and give her smile more profile (if needed and appropriate) This may work or it may not. hopes it helps
This is why I'm annoyed at people who think 'clopfics' or as I like to call it, My Little Pony Erotic Fan Fiction, are evil. We can safely assume ponies have sex. Why would it be so wrong to write about it?