The reason Python is used for the API is because the editor is cross-platform, and Python is the best choice for such a situation. If you want to run other scripts or programs, you can use the python subprocess module.
If there is something you are looking to tweak, http://sublimetext.info/docs/en/ has a lot of good info, and the forum (http://www.sublimetext.com/forum/) tends to be a pretty good place to ask questions.
Probably a multi-ms delay due to regexes for syntax highlighting.
And TextMate is not designed like a standard OS X app, either.
I always liked the file browser column in TM better.
> I've yet to figure out how to open a project directory from the GUI, too.
What's wrong with File -> Open Folder or Project -> Open Project?