I'm not really go into details about this, but basically they cut allies out of both codices. By this I mean, other armies cannot requisition the use of Witch Hunters or Daemonhunter units. So that means no more Brother-Captains for the BT. He was our primary and best method of psychic defense. No longer.
This was likely a knee-jerk reaction by GW to prevent abuse by Imperial Guard players, as was being seen in 'Ard Boys. The whiners complained just enough I guess. Either way, GW didn't look at the more broad consequences of that decision and their effects on other armies such as ours. Still, we'll continue the Holy Crusade as we have always done. I cannot say it wasn't half-expected, so I cannot be too angry about it.
However, because of the changes, I have to revise and play-test several of my lists to account for the loss of the Brother-Captain. This might take all day, and I MAY have to push back re-publishing the BT 101 guide till tomorrow. Personally, I think having updated lists with analysis is more important overall to players who might come knocking in the next day or so.