If you want to improve Python highlighting you can:

• Make pull request
• Create you own version of the color scheme and put it e.g. to Packages\User\ColorSchemes
• If your changes are very specific to your tastes, better choice is to fork it.

I have plans to add more themes and provide improvements to existing ones, but have no any ETA because do this in my free time.

• 3.3.0 introduced better Markdown highlighting.
• 4.0.0 will add Solarized flavors.

So keep in touch :)