I love the web preview feature but it would be handy if could specify QueryString parameters when doing a preview. Many of my ASP pages use the QueryString but I am unable to preview them directly because I need the parameters passed in from another page.
Also, the Taskbar is a little difficult to use, and I often find myself wanting to click on one of the preview tabs instead (I'm used to this from Homesite). I'd prefer more of a tab-style document selector, but I'm sure I'll get used to the Taskbar if it doesn't change.