CS5 HTML5 Pack doesn't cover very many browsers. For gradients, I'm better off using:
Your product doesn't seem to generate border-radius CSS at all. What about box-shadow and box-shadow:inset?
If I could use Illustrator to generate actually useful cross-browser CSS, I would upgrade to CS5. As it stands, I see no reason to do so.
Do you have any plans to complete this project? Is this project dead?
The HTML5 Pack for Illustrator is provided by Adobe in beta form. Adobe often releases technology so that users can try it out and offer suggestions for how they might use it. It sounds like you would like to see some additional attributes added, and I'm sure a feature request would be a good idea. The more Adobe understands how we as users would use it, the better they can tailor it for our needs.