WIP Rearing

This is an unfinished sketch of a rearing stallion. I feel there's something not completely right about its proportions but I cant put my finger on it. And now that I see on screen I'm thinking its oke... Maybe you can see something that needs improvement?

I dont know wether I'm going to finish it as a coloured piece or just a graphite piece. The shading and highlighting isnt up to standard either. I dont like the way it is. But then again, it is a work in process!

Sorry for the terrible erasing, my eyes started hurting and I rushed through the cleaning up process....

Graphite pencil 4b on printer paper, 20x30cm.