Many users leave misguiding comments on off-topic questions that they consider on-topic on another site. To battle this, allow users to select all sites in the migration dialogue, but instead of migrating, leave a constructive canned comment and flag for moderator attention, if the question has answers.
Change the dialogue for Close → Off-Topic → Migration and Flagging → Closing → Off-Topic → Migration as follows:
Below the existing targets, show a search field that allows the asker to select every site in the network – similarly to what is shown to moderators right now (looking like this). Implement this proposal and show the target audience of the selected site.
If the question does not have any answers¹, create a canned comment like this (taking a migration from German Language to Academia as an example):
Have the vote count as a normal close vote, but do not initiate a migration or raise an automatic flag.
If the question has answers¹, raise a moderator-attention flag and leave a comment:
I’m voting to close this question as off-topic because it is not about the German language. Your question has flagged for migration to Academia SE, where it may be on-topic. Please wait and do not repost it.
¹ Negatively scoring answers can be excluded from this.
A frequent source of trouble and frustration for new users is if they ask a question that is off-topic on one site and are recommended to ask it on another site where is not on-topic either. Moreover, even if their question is on-topic, many of those questions would benefit from the asker reading the respective site’s guidelines (and Stack Exchange’s guidelines on asking questions in general) and amending their question accordingly.
Thus many comments recommending another site could be improved by being more moderate in their claims what is on-topic on other sites and linking help pages, which can allow the asker to decide upon the on-topicness or to improve their question before reposting it. The suggested dialogue facilitates such comments.
Many users are confused whether to recommend migration or reposting with off-topic question that are on-topic elsewhere. Having the system
help themmake this decision for them, alleviates this. Moreover, this way, moderators only have to deal with migrations that have some benefit, i.e., keeping a possibly valuable answer.
Showing users the actual scope of some migration targets may prevent some wrong migration suggestions (see here for more arguments).
Users who already post helpful comments on such off-topic questions are spared some typing work. For example on Academia, which gets a lot of off-topic questions that may belong on some science or programming sites, I type comments as suggested above for questions without answers on a daily basis.
As no migration is initiated if the question has no answer, more often the asker is responsible for reposting it. Thus questions from askers who cannot be bothered to care about their question are less likely to end up on another site. As such askers also do not tend to put much effort in their questions, this might considerably reduce the problem of crap being migrated.
While some users will continue to give bad migration advice, their numbers should at least not increase.