My current situation: I'm working on a "team" (one other developer) to create several sets of dashboards, all using some combination of 3 data sources. We are connecting to our tables by publishing and then connecting to data sources on Tableau Server rather than connecting directly to the Oracle database. This ensures we're looking at identical data (not having to worry about inconsistent table joins) and we have access to all of the same calculated fields.
The problem: When we add calculated fields or change calculations we want to push these changes to the Tableau Server data source. However, in order to update the data source on Tableau Server, we have to create a local copy of the data source, open that local copy in a new project, add/update the calculated fields, aliases, or field names, publish the new connection to Tableau Server (overwriting the old connection), then close out of both projects, relaunch Tableau Desktop, and reopen the original project. This is a horribly tedious system that slows down our workflow considerably, and god forbid you make a bunch of changes (like I just did, hence this post) without creating a local copy first, you have to create the local extract and then go back and track down every single change you had made.
The idea solution: There has got to be an easier way to modify data sources that have already been published to Tableau Server. Since the ACL on the data source specifies who can edit, there should be an option for anyone with edit privileges to push changes to the data source on the server.