How can we improve WHMCS?

There are many, many deficiencies in WHMCS reporting. I saw someone suggested the ability to generate a detail Accounts Receivable Aging. This would be very beneficial, but I need something more. I actually figured out how to run an detail AR aging as of a specific date. I've proven that it is correct. It requires Moldule Gardens Report Generator, or you can do it manually in Excel. Either way it will not include prepayments,. which it should. The AR summary aging in reports also does not include prepayments.

However, when I try to rollforward from one AR aging to another I run into difficulties. There should be a canned detail report which will roll forward accounts receivable. It's format would be Beginning Balance, Invoices, Credits, Write Offs, Payments, Refunds, and Ending Balance. In general I am having to piece together reports to roll AR and I run into issues every month.