Hello df8oe,
metapackages are convenient to install, but maintaining such sid installs isn't.
Especially the gnome package makes use of hard dependencies to pull applications.
As a consequence it will break each time, when a glitch in packaging happens.
E.g. packages gnome and quadrapassel in sid/amd64 are linked by hard dependency chain:
gnome ▶ gnome-games ▶ quadrapassel
This means you can't keep installed the gnome or gnome-games package without the quadrapassel game and the debian gnome maintainers want this behaviour. Even the debian stable release tends to break
https://bugs.debian.org/715555 (because back in wheezy you couldn't have gnome without xul-ext-adblock-plus).
siduction doesn't install metapackages but maintains a list of packages and allows the user to modify the selection. Well, recently we have had discussions about this design. Feel free to comment.
greetings
musca