How can we improve WHMCS?

WHMCS offers no way of checking to see how an e-mail will look once you've edited it, short of making a fake account or waiting until a customer receives one, which isn't the best plan if you've screwed up a "merge field" and it looks terrible / doesn't work.

It would be good if you could make it so you can click a button and it pops up with a window or shows an area on the page showing how the e-mail would look if a customer received it (with false data, just as long as we can see it's doing / showing what we want to see!) without having to faff about with fake accounts.

Twice now I've noticed that I've made a mistake with an e-mail template without realising it, only finding out later when checking what e-mails customers have received...