Wow, just looking between your old version and this one you can see all the differences between your style and technical skills. It's so crazy to look back at stuff right? Looks awesome can't wait for more!
I like seeing artists' old work too and my own. I like trying to figure out what things were important to the artist at any given time aside from content. I think that if you can figure that sort of thing out and see how they went about improving those areas it may be applicable to your own work or at least give you a starting point.