How can we improve WHMCS?

I'd like to be able to personalise the domain email templates based on the domain payment method, so that I can advise people how payment should be made in the renewal warnings and to match the text to the invoice (different text for bank transfers, card payments, direct debits etc).

This would greatly cut down on confusion when clients receive the renewal reminder as we can e.g. simply tell them "we take your automated payment on due date, you don't need to do anything" or warn them to make a manual payment.

The variable I need in the domain email templates is "Payment Method" on the Domain details page.

Many thanks!