I am thinking on the concept of keeping debs and related files, it does not seem to require too much code change but also perhaps introduces the need for a basic import configuration file so one's common options, like SECURE or KEEPDEB can be set so a combination of command line flags would not need to be issued on every import. "import -f" of course would remain a flag, but the two and in the future perhaps others can be set in a config file for the sake of simplicity so forgetting to use a flag for keeping debs would not wipe out the directory of downloaded files that would be cleared by default without a flag or config file option. The config file when left alone or modified the values within would be used unless overrode by a flag.
I use a single 500MB mydesktop.sce file made from a file list, and with this option and the set of saved debs and related files, say if I was interested in updates to openssl, I could do an update check on the large sce and when an update is available. Then I could re-import the mydesktop file and it would only have to download the openssl package as well as any other available updates, which would be surely small compared to the entire set of debs that the sce is made of.
I will arrive at the concept, put it into code, and present it to the team in the near future.