cPanel/WHM test license
Since it is not uncommon for organizations to set-up a non-public production-like test environment it will help if cPanel provides a test license possibility. This way the behavior of new cPanel releases can first be tested before the production deployment. Especially in combination with applications like WHMCS (billing automation software for cPanel/WHM servers), recently a partner of cPanel, the risks are higher and automatically results in the business requirement: test before taking into production. I am aware this is not exactly a feature, but I do believe that providing test licenses will help a lot of companies to fulfill the test requirement.
WHMCS provide test licenses, most domain registrars and payment gateways provide test environments so the only test environment in a production-like set-up that is missing is the core platform: cPanel.
Note: this is not the same as the cPanel development licenses. These are only provided for actual development to the cPanel platform.