Updating services is the biggest hindrance to using ArcGIS Online (AGOL) in its current version. There are more than a dozen posts in the forums related to the issue and although there are work-around solutions they don't address the difficulties in maintaining what could be a vast library of map products and services in each organization. I'd like to propose a few ideas on how to do this:
Proposal: All of the information for publishing a service should be stored directly in the MXD. Problem: If a service is not published right away it is saved under Drafts, but once it is published the draft goes away. These drafts hold a lot of valuable information such as metadata, credits, and map functionality that go to waste once it is published. Drafts are effectively a template for how the service should be published each time. Currently the only options in ArcCatalog for Drafts are Open and Delete. Idea: If the input fields from the Service Editor window were incorporated into the Map Document Properties window as tabs it could alleviate the need to fill in all of the required metadata fields and adjust the settings each time a service needs to be published. Fields for Access Use and Constraints need to be added to this window and default attributes for these fields should be allowed in both ArcMap and ArcGIS Online especially for organizations. These last two suggestions have been submitted to the Esri Ideas page (see hyperlinks and Promote them, please!).
Proposal: The HTML Popup tab from the Layer Properties window in ArcMap should be used to store the ArcGIS Online feature service pop-up information. Problem: It is lengthy, painful process to reconfigure the feature service's pop-up windows each time a the service is updated in AGOL. Idea: Reconfigure the ArcMap HTML Popup window to include some of the same functionality from AGOL with the ability to add charts, hyperlinks, change fonts, use dynamic text, etc. Allow the configuration in ArcMap to carry over to the feature service in AGOL.
Proposal: There should be a way to trace the occurances of services within Web Maps. Problem: Once a feature or map service is updated there is no way of figuring out how many Web Maps will need to have the service replaced with the updated version. Idea: There should be an inventory tool that can find the occurrences of a service throughout the Web Maps in an organization.