raison d'être

I don't think it matters that no-one uses the tool for long so long as the tool does help get over that ramp. So a tool could display the appropriate existing documentation for the distribution for debian/control (and hence what "pre-depends" means), when pre-install scripts run with what arguments in what situations, etc., maybe a link to a Bourne shell reference, and so on. If the only thing that the gui does is help you find the right documentation, then that can still end up having a really positive effect on the existence of knowledgable packagers — i.e. forming part of the answer to "how can we best cultivate new packagers?".