I would love to work in collaborations but I don't have much time because, unfortunately, pixel art and game dev are not my main job. But please send me an email to rgsdev83@gmail.com so that you can give me more details about your idea. If I'll can contribute with my free time, it would be amazing!
By the way, what do you mean by clunky characters?
I always test my assets on the game engine before release to ensure that it will be easy to use for anyone, so I accept suggestions on sprite structure or any other type of problem you may notice.