I have three suggestions that would be extremely helpful when you do upgrades/enhancements on Site Catalyst:
1. Send out to your client base notification of what you are about to do maybe through an EDM. "We're upgrading Site Catalyst on x date and these are the benefits/changes you can expect to see" etc. This allows your users a heads up on what's happening.
2. If there is a hiccup with the upgrade when it goes live, immediately email out again to your client base what the issue is and if possible what time you expect the engineering team to have it fixed. You could go one step further an include a voicemail message at the beginning of the Client Care voicemail message, "If you're calling about difficulties you are experiencing with our latest upgrade, please be aware that our client care representatives are aware of this issue and the engineering team are working on fixing this". This would prevent the large number of calls through to your client service representatives who are having to repeat to multiple clients the same message.
3. Finally, tell your client base when the issue has been fixed so we can go back in and use Omniture again. This will prevent large numbers of clients visiting the site every hour to see if its fixed.
It's not called Rocket Science, more like proactive client communication