* Because the admin toolbar styles are displayed in the <head/> tag block, it makes it difficult to override many of the styles (even using the !important option) thus the admin toolbar looks different on different site designs (and difficult to override).
* The styles do not validate making it difficult to check site validation without constantly logging out (sometimes we need to be logged in to validate secure areas on the site).
* IE-specific styles should be in their own style sheet(s) rather than using the "* html" hack.