There are a number of reasons why migrating to stack overflow is a good thing:
- People who ask off-topic questions on Code Review are able to get answers to their questions (even if it is on a different site)
- ....
Hmm, that's right, there's only really one good reason for migrating to Stack Overflow.
Now, until recently, in those cases where a question can be migrated to Stack Overflow, only a moderator could migrate it. Let's look at some recent statistics... in the past 3 months, 15 questions were migrated.. that's one question a week. So, clearly, we are not talking about heavy volumes.
Those are the questions that were migrated successfully. In my previous moderator experience, many times the migration failed because the question asker is question-banned on Stack Overflow - they come to Code Review because their questions are not allowed there.
In addition, migration requires 3-migrate votes (a majority) before it happens, so, it's a numbers game: 3 people vote to close as "off-topic - broken code", and the other migration votes don't work.... which will lead to flags anyway for moderators to intervene .... or, nothing.
Further, it will encourage people to answer off-topic questions here on Code Review if they anticipate that the question will be migrated away, instead of closed. Someone asks a broken-code question, may as well answer it here instead of waiting for the migration... right? Then, the migration does not happen, but we still end up with a culture of answering bad questions instead of closing them (Oh, and don't forget there's a double-reputation bonus - any upvotes you get on Code Review will be applied to Stack Overflow too....). Hey, it also solves a FGITW problem - you can get your answer in before the gunslingers on SO.
Finally, the close-vote privilege is obtained at 500-rep, which is far too low for a site to have migrate-away privileges.
So, in summary:
- it's a problem that does not need a solution because it is a tiny problem to start with
- almost all migrated questions need to be heavily edited before migration because Code Review questions are not great SO questions.
- many questions deserving migration can't be migrated because the askers are Q-banned on SO.
- it encourages people to answer off-topic questions because they anticipate a migration
- the people voting to close may not have enough experience on our site to decide.