IAM in Service Catalog
Although pre-installing the root certificate on systems within your department that you manage can significantly reduce the support burden, it probably won't eliminate it. Therefore, if you plan to deploy a certificate issued by the UW Services CA you should be prepared to support your user community and answer some questions (see UW Services CA FAQ).
If the size and nature of your user community suggests that this support is going to be difficult, it might be better to purchase a certificate from a well-known public CA, such as Thawte, and wait until such a time that the UW Services CA root certificate is better deployed within your user community. An InCommon-issued certificate may also be a good option in some cases.