Right now, when I flag something as off-topic, I can choose from a pre-defined set of "blessed" SO sites to suggest for migration.
I see there are already a lot of questions about this design choice and the prevailing opinion is Don't Make Me Think which I agree with entirely. Rather than arguing to have the list changed or a pet site on the list etc., I propose adding one more box at the bottom for "other" with a text entry to allow the flagger to put in which site not on the list would be better suited.
There can be a validation on the backend to ensure it's a valid site and not just random garbage. Most of the time I'll put the site I think it should be on in the comments to the question and then flag it, which is functional but requires more "thinking" than having an "other" box. Or a drop-down list of the missing sites for up-front validation.
Along similar lines, a suggestion to flag as "it needs ♦ moderator attention > other" rather than flagging as off-topic was made which would also serve the purpose. But that to me again breaks the "don't make me think" approach because now I have to decide whether it's off-topic and there is a blessed site for me to suggest or if I should flag it this way where I can put in anything I want.
What are the thoughts against having such an entry box? I think it would clarify the workflow and require fewer steps and/or thinking than the current system.