I would like to see a feature added to build and execute Test Cases. Something like Test Rail. This way the users could track pass/fail on each test case within workfront and fails could trigger an issue on the testing task.
There doesn't seem to be much on the market today aside from Test Rail. JIRA and VSTS have automated testing built in to them, but there is almost always user testing required. If Workfront could add this feature, it would set them apart from the competition.