[currysausage]

What if I prefer a predictable release cycle for the base OS, but still need the latest LibreOffice/VLC/_____ for one reason or another?

I like the approach taken by e.g. Nginx and MariaDB, where I add additional vendor repositories, but this workflow is probably neither user-friendly enough for my mom, nor have all vendors the resources to maintain several repositories for different distributions and their respective versions.

[vbernat]

Use an OS with backports, like Debian. For example, if you took Debian Jessie, you could pull LibreOffice 5 from backports. VLC is already almost up-to-date (2.2.1).