If it allows me to run arbitrary Javascript on my blog, this would already be a huge improvement over Wordpress. This is not to mention having to pay to control the CSS just to fix the theme designers' bugs and horrendous CSS practices.
Err - you seem to be talking about WordPress.com, i.e. their hosted version.
If you host it yourself (from WordPress.org) you don't have to pay for fixing/changing stuff as well as have more freedom to do with it what you want.