have a look at the TODO-section in doc/amavis.txt

* improve resource usage and performance
* modularise configuration
* improve testing/debugging facilities,
  add more tests for different functions of the script
* make test suite work with qmail
* add SMTP facility to use postfix new content filter interface
  for input, too
* add configuration support for a cut-down version of the script
  to use with macofida
* problem: decoding of nested forwarded messages with both
  MIME and non-MIME components
* AVP configuration issues
* amavis-milter: use other means of creating *secure* tempdir
  where available (*BSD)
* ultimately: rewrite as daemon
* relax configure requirements for availability of decompressors,
  and implement policy how to deal with un-decompressable files