I think as we graduate, it's good to encourage visits from related sites, particularly Physics.SE, Biology.SE, etc.
I often find some questions on Chemistry.SE that could easily be on Physics and vice-versa.
I'd like to encourage supporting a Meta.SE feature request for sharing questions between multiple sites.
This proposal would offer an alternative to migrating questions. Instead for topics (e.g., quantum chemistry) that are shared between sites, questions could become "crossover" questions and appear on multiple SE sites.
What do you think?