My understanding is that Expression Web is a tool for web designers to be able to work with the styles and layout of a page without a tool set specific for the task at hand. It doesn't include tools for maintaining a whole project because it's intended to produce just a layout (or individual web pages).

Having said that I never got it to work on my machine when I tried to install it (That was the beta though and I haven't tried since). So my understanding may be flawed.