This already exists to a limited extent and doesn't work very well when general users do it, often resulting in questions getting slammed closed on the receiving site and pissing off that community.
You can still get this to happen by flagging it for mod attention and putting the move request and justification in the message to the mod.
In my experience, only about 5% of the time is a migration valid because most questions that are off-topic are poor questions to begin with. Beefing up the migration capabilities of the general population of users (ie. non-high-rep, non-mod) will just propagate garbage to other areas of the Stack Exchange ecosystem. I would much rather not add pollution and increase global warming.