Best Universal Package Manager for Linux?

Suddenly, Linux needs a universal package manager for installing software. At least, that’s what Canonical Software claimed when it introduced its new Snappy packages. However, if the need is there, which package manager should be adapted?

Mind you, the necessity is far from obvious. Canonical has been using the Debian package manager for over a decade, apparently without major difficulties. Moreover, Debian maintainers insist that the solution to any problem is a well-defined package format, like the Debian Policy Manual.