I have often experienced major inefficiencies with upgrading huge bunches of similar packages in Arch, because after each single package installation or upgrade a post_install() full of expensive cache refreshment calls is executed.

Examples for that are the kde packages with "xdg-icon-resource forceupdate --theme hicolor &> /dev/null" after every single application that uses icons (which are quite a lot) or even worse texlive which updates the whole tex cache. This can multiply the installation or update time on slow systems or systems with lots of icons/fonts installed.

My suggestion would be to introduce some kind of "shared" post install instructions. Every call to those during the installation/upgrade would be listed and in the end only one of a kind is executed.

So in the texlive update every package has the shared post upgrade order "tex-cache" and only after the upgrade was finished the tex-cache order would be actually executed.