I noticed that in the thread `A devuan "constitution"` that you were talking about what packaging system to use (what that has to do with a packaging system I have no idea).
But first, for the poor slackware user: Seek the install files and they should list all the dependencies of the packages you install.
IMHO apt is an insufficient means of package managment. It has very limited querying capabilities and tends to lump tons of packages into each catagory, and there aren't many, thereby making browsing the lists very difficult. IMHO, we should, or could, use an sql database to store the information. This would make breaking the dependency system simple as there would be nothing begging you "but what about this, that, and the other package...." (there are reasons to do it.) It would also solve rpms problem where a package _must_ be installed to learn anything useful about it. If you used postgresql, which I've worked with extensivly in a project I'm writting in C, you could use * and ? wild cards as well as regexes. I could write a simple CLI front end, if I was given a little time I'd write a GUI frontend in tcl. Importing the data could be just as simple as a restore command (but you'd have to download the the online dump first of course).
I'm not very familiar with dkpg though I've heard that, like rpm, it has it's drawbacks.
I think something more flexable then either might be created.

David