Another thing I would love to have is a preview feature, in the case that I don't have to deploy my application, load the browser and see a rendered JSP. Having a preview pane like Dreamweaver can be amazing and useful feature. Does IDEA7 has something like that?
No, there is currently no such preview feature in IntelliJ IDEA. Note that in most cases previewing a JSP will require compiling and deploying the application anyway, because of the dynamic code that can be contained in a JSP.