How can we improve WHMCS?

Here's a list of problems we see with current global (enabled for everyone) prorate functionality:

Marketing campaigns:
Initial fee to pay almost always is different then the price tag. This creates confusion and probably increases bounce rate in our campaigns and funnels.

Limits flexibility for developers hosting many sites:
The client is locked to pay everything on one day. W have clients who are developers and host 50+ sites with us under one account. They constantly request to change the due dates for groups of their sites. This allows them to pay for groups of sites associated to their end clients on different days, invoices and with different cards.

Solution - prorate option in checkout:
Checkout should ask the client what day of the month you want to prorate that order to and calculate the fee live there.
This way the fee in checkout will be the same as the price tag in our marketing campaigns and client will still retain the option to prorate if they need to.
Additionally big developer account will be able to group their product by due date while ordering cutting on the frustration and support tickets load.