Could we know the details of how the current migration to ELL from EL&U works? I think that in general the migration path is a good thing. However, I'm a bit worried that there might be some counterproductive aspects to the way it currently works.
The impression that I get is that questions are being migrated as soon as 5 vote-to-close votes are assigned to the question. I also think that maybe some mods or high-rep users may be getting these questions migrated unilaterally or with another vote or two. In principle I'm not averse to this, but in practice, it seems to me that there might be a bit of a problem here.
The problem is that some questions might at first look like language learning questions, but may in fact be of huge significance and interest for linguists etymologists and serious English enthusiasts. In particular this applies to questions about grammar and syntax (yes, I know, syntax is part of grammar!). It can sometimes be very easy for people who care about the site, but aren't familiar with certain developments in modern grammar, or classical problems, or just interesting questions to migrate questions because a) they know intuitively what is grammatical, and b) because the OP is not a native speaker.
The kinds of questions that I'm worried about use losing are questions like What is a noun, What is a question? Can a word or phrase be a subject and an object at the same time?, What is an adverb? and so forth.
Now, when questions get closed unilaterally by a mod or get five down-votes, there is the opportunity for the community to vote, and if necessary appeal here on meta, to get the question reopened.
If a question gets migrated to ELL, does this happen instantaneously after it gets the necessary vote? If so, could this be changed so that there is an incubation period so to speak, where the community has a window of a couple of weeks to get the question reopened if it is in fact of value to us here at EL&U?
4. There's a high probability that users of site Y would enjoy seeing the occasional question about Xon the FAQ page