How can we improve WHMCS?

While I could go on the many features and updates I believe the Licensing Addon needs (and may do so as it was last updated in 2012), I believe the ability to Limit downloads to Clients is in order.

By Limiting Downloads for Clients would prevent abuse not only of the downloads but if the download were a Support & Updates Addon, you could limit the client to download the product for the addon a certain amount of times. This would especially be beneficial if the person selling a software created something like setup.php and they used an auto-updater, such as the one in WHMCS to handle updates. Again, if the support & updates subscription expired, and it was done this way, it would have to force said client to re-subscribe to the support & updates subscription so they couldn't just go in and grab the latest version at will.

If you need me to clarify this, please let me know.

Again, many changes are needed to the License Addon, and this is one I believe would be very beneficial.