Require or exclude domain addons/features and skip domain configuration page.
It would be great if whmcs had the ability to force (or exclude) certain domain addons per product bundle and skip the domain configuration page to make purchasing bundled products/packages easier than ever. So for instance, if you have a certain product bundle or product that caters to a certain group of customers that need something like dns management or id protect by default or totally don't want it. Instead of having the customer configure it at checkout, admins could just require it (or exclude it) so the customers don't even have to see the domain configuration page and have an incredibly easy checkout experience. The domain configuration page is just another step that can hinder conversion in certain scenerios.