tetsuya, if you've been doing pixel art for 10 years with commitment and you consider yourself a purist (I read from this, dedicated to the craftsmanship and learning) then you should have learned how to draw horses, along with buildings, telephones, sad girls that have just been told their flights have been indefinitely delayed, sleepy cats, sports cars, washing machines, big trees and small bushes, cruise ships, children and other things in those 10 years. If you haven't learned how to draw those things (through practice, adoption of good methods that allow you to abstract nearly anything into shapes and forms you can represent in your artform) then you don't really have 10 years of *experience* with artistic creation, you have 10 years of dabbling in it.
Not saying that's a sin or anything, that's fine, but get your head straight as to what your skills add up to and if they're ways away from what you'd have liked them to be after 10 years, then it's time to practice more and better. You seem to be distressed with something else than you should be at.
A good place to start is to stop thinking about how much of an accomplished pixeller you are and confront how much of a pencil artist you are. If you can't do it with a paper and a pencil, you won't be able to do it with pixels. This is a sad truth for a lot of people that got into the arts through pixel art (and especially game art) in the first place where they throught that if they could fumble away in a little 32x32 box until something looked marginally ok, they 'could draw'. That's an empowering feeling at first (because truly, everybody can draw if they put their mind to a method) but it's also crippling later on when they've drawn a few mockups of game art and think this translates to the skills of a non-pixel artist of equal representational-drawing strength.
If you want to know your measure as an artist, draw something to the best of your ability on a piece of paper at a serviceable size and post it on some community (here or elsewhere) for critique without any preamble of how much of a purist or how many years you've been drawing attached to it. Reactions will steer you in constructive directions to better yourself. Don't hide behind small pixels, don't hide behind game art.