Debian packages have a much simpler design than RPM. This makes it easy to unpack them even without having dpkg installed, as it is just an AR archive with two tarballs.
Now, some of my thoughts on your comment, from my Debian PoV:
> * Gpg verification, IIRC in RPM based systems first
Binary packages can have signatures using 'debsigs'. All source packages are GPG-signed and the package repositories are signed as well, and supported since apt 0.6 in 2003 (though it took some time until the main archive was signed for the first time).
> * Multi-lib support (next Debian release goal)
Well, at least Fedora had the problem that it always installed packages for both architectures, although they were useless for me. But that was a long time ago.
> * Automatic debug info generation (next Debian release goal)
Yes this will come.
> * Delta RPM integration
We have debdelta.
> * Separate patches
What do you mean?
> * File capability support?
Write a script to set them. But I don't think we really need them at the distribution level.