This extension has been born out of several shortcomings in the original directmail extension, mainly:
Non-intuitive setup of directmail. IMO it is nearly impossible to setup and test directmail without consulting the manual several times. The fewest of our customer's really gets the hang of it. Especially the “fetch and compile”-stuff is hard to understand. The old extension also seems to have several pitfalls.
Limited configuration. The concept of categories and the possible source tables, are often too limiting. Often I would like to use a lot of different fields, sometimes from different tables. It should also be possible to make these configurations in an user friendly fashion.
Overflow/multisend problem. Way to often we have had problems with multiple dmailer processes starting on top of each other, sending the same mails multiple times, because the first one failed to finish in 60 seconds. I know there are workarounds, but I would like a more robust setup.
I addition to this I would like to make the mailer faster, and to make possibility of periodic mailing. So we can schedule the directmail to be send later on a day, a week or other common amounts of time.