See, I suppose I have a different view of how involved Joss ever was with AtS to begin with. He was never the one in direct charge of managing the show. AtS was, at its birth, very much David Greenwalt's baby with Joss maintaining his focus on BtVS. Then it became Minear's baby while Joss focused on BtVS and later Firefly. And then it became Fury and Bell's baby, while Joss focused on talking people into making Serenity. Not to say that Joss didn't contribute essential things to AtS (he was the one who thought up that Darla be pregnant when she returned and thus he initially thought up Connor). But most of the actual running of "AtS" fell to other people. That's the way that Joss always handled the Angelverse. He was never particularly hands-on with this show.