"The things you can do in WPF, Flash can't do," Cuenco said. For example, with Expression, developers will be able to build interfaces or "skins" on top of business applications that can be easily swapped out by users or customized to make them easier or more powerful to use, Cuenco said.

Despite Microsoft's hopes, it may be counting too much on the ubiquity of Windows and the popularity of its .Net tools among developers to help make inroads against Adobe, said Joe Wilcox, an analyst at JupiterResearch. "Adobe is the incumbent here, and as we've seen, incumbents are not easily displaced."

One reason is that while developers may see the benefits of adopting Expression, designers may not clamber on board. "Microsoft is operating under the presumption that when the developer and the designer work together, the developer is the lead. I'm not sure I buy that."

Microsoft also faces skepticism because its most prominent earlier effort, FrontPage, did not win a strong following with professional designers. In February, the company said FrontPage would be phased out, with its features being incorporated into Expression Web Designer and SharePoint Designer 2007, part of the Office 2007 suite.

"Expression will automatically get a lot of resistance from design houses because there is a lot of emotion tied to the [Adobe] brand," Cuenco said.