Untill its done. Noone really knows how long it will take. I would guess around 2-3 months. I think thats how long it took when MoP came out
MoP came out 25.09.2012 and on 28.9.2012 i already had bots running archeology so definitely not 2-3 months. Of course questing takes way longer but you can expect (from previous releases) a feature limited/functioning version being available in the first week.
Are you sure? I Still remember all the threads from hb users that didn`t know how to play their toons flaming around here in the forum. And the devs asking for at least some running version of hb to start creating profiles. But maybe I am wrong and that was at the cata release.
I know that kick is working on the questing stuff in beta because in the questing profile pack you see 90-100 files so we can only hope for the best
In one of the "When will HB be WoD-Ready?"-threads, a mod (Tony iirc?) said that they already had a working build for the Beta realms. Assuming that a couple of things change every beta build, Id say we could be botting again within a couple of days after 6.0 release, provided that your combat routine and botbase are up to date. I cant find the post now though..
blizz probably will release WOD with some kinky antihb stuff, so even if it works in beta now they probably have something for the actual release to fuck us up.. :/