I understand that you're having people pay for customizing their CSS. It's great value to be able to customize your theme and a price can rightfully be charged for that.
But what about those people who just want to change the size of their tagline? Or their list icons? Or the margin for inline images? Simple things.
What do you think about the idea to allow wordpress.com users to use a maximum number of characters of custom CSS for free? That would allow people to make simple changes while still retaining the value of a custom CSS upgrade. I'd love to hear your thoughts on this.