One big flaw is that there's now no generic "off-topic" close reason.
There are tons of crappy questions that are arguably on-topic somewhere else but you're not supposed to migrate crap. The generic "not related to professional sys admin" close reason was perfect for them - close in place, w/out fobbing them off on SU or UL (and then possibly having them bounce back 'cause they're crappy.)
Of the 10 close vote reviews, the old generic "not related to professional sys admin" would've been my choice for at least 1/2 of them. The new wording doesn't fit, but I still picked it as being the closest.
(And no, I am not writing custom close reasons... for the amount that I close vote, that's not feasible.)
Update 1 day later (Merry Christmas!) - It looks to me like this is going to be a problem: of the 10 close votes I just reviewed, 7 of them had "migrate to another site" showing, and at least 5 of them were crappy questions. I'm certainly willing to wait and see how the actual stats turn out, but it looks like a lot more crappy questions are going to be closed and migrated to other sites with the generic close reason gone.