I would like to see the Announcements functionality updated to allow linking to other things than just 'Services Involved'. Our Service Catalog is much too broad to allow this field to be meaningful to the end users. I've seen several other Ideas over the past decade asking for the same functionality, so I know this would be an important enhancement for your customers.
For instance, if I am performing scheduled maintenance on a particular application, I need to make this stand out for my end users. Particularly those users who are entering support issues from the portal, but may not have read the announcement.
If other customers prefer the functionality of the Service Category, an alternative might be to add a Tags function to the Announcements. This would allow customers to add a more granular category, say for a particular application or asset.