First of all: Thank you for this detailed review :)
What you said about the mane: I really had some problems with it. It didn't turn out as I wanted it... I don't know why, but apparently I'm not good in drawing hair or mane... Have to practice, I know.
The problem is that this is a photo, cause I cannot scan A3 paper, it is too big. The contrast better turns out at the real drawing; there the mane is black and some other things are darker... I know, it sounds like a bad excuse, but it's true :D
I was a little bit afraid of drawing the bridle darker because I thought it would degrade the shadow... But maybe it wouldn't have done it... Well, I can't change it anymore, but you're right in saying, that it would have looked better.
The thickness of the lines is a problem I always have :D I do not want to draw outlines, but I need them for my conceptual design, so I have to erase them or try to use it as a shadow line (as I tried it by drawing the bridle).
And: Thank you for liking the eye (and the work around it)! :D While drawing, I never was happy with it and erased it a thousand times, just to draw it again... Additionally the eye never turned out as the one of the real horse looks like... I'm still not happy with it :D
So, thank you very much again and I have to say that I am really happy to get those compliments and 4.5 Stars of you because I always was fascinated by your artwork (:
Thank you :)