Installing a website is pretty straight forward by just coping files onto a web server and configure a new site in IIS.
We will not make a MSI package if this is not highly requested.
We have used MSI packages for Publech in previous versions and these are some reasons for not using MSI.
It doesn't make it easier than in IIS
Most Server Administrators want to have control over the settings in IIS and don't want a installer changing these settings automatically.
If you use web hosting you probably can't run a MSI package on their servers.
What we probably will do is to make a startup mode in the website so that when you run the site for the first time you get a wizard for setting some configurations and creating the database by script and not by a backup like today.
In this way the Server Administrator / or Web hosting user have control of the creation of the website and the application specific settings is done in the application.