Jeff Lemire, writer of Animal Man and Sweet Tooth for DC, is the new writer on Justice League Dark from issue 9, following the more mystical member of the DC Universe who may have previously appeared in Vertigo books, and their attempts to save it collectively.
Lemire has already done this successfully with Animal Man, it is probably DC's hope that he does the same with the Constantine Scooby Gang.
Mikel Janin will remain the artist in the comic. And writer Peter Milligan will continue to write Constantine in his Vertigo title Hellblazer and is, presumably, still on Red Lanterns.
BTW, have you all read Jeff's Essex County? You should.
UPDATE: And Peter Milligan takes over on Stormwatch from #9 while Matt Kindt takes over from Jeff Lemire on Frankenstein: Agent Of SHADE form #9. Here we go round the mulbury bush…