At present you can create a web application on ArcGIS Online using one of the templates provided. Some of these have the capability to tweak the look and feel of them. They also have the capability to download the template and tweak the code to further configure the web app but you then have to host this on your own web server (even though all of the data may be coming from ArcGIS Online).
It would be great for those organisations that don't have their own webserver but want a more customized web app if they could host these alongside their data in their ArcGIS Online for Organisations Subscription account.
