Your build server has everything to do with deployment. Your build server should be the only place production builds should ever come from. What you seem to be suggesting is replicating a build server for deployment. To me that seems like a violation of SOC and DRY -- but applied to infrastructure rather than code.

Once you break out staging from production, which you should do anyways, I don't think there's any issue left from the things you listed. And the additional benefit is I don't have to learn another framework like Capistrano.

With that said I do think deploying w/ ASP.NET is a pain, but not for the reasons you mentioned. But because getting the configurations working in all the right places is painful, IMO.