Some interesting points raised over this.

Moving the "group study" as a KH meeting would mean they can see who has turned up.
Many JWs did look on the "group study" as something they could miss now and then without any worry.
I know some with young children would take turns to come, mother one week, father next.
So the children didn't have to come out just for an hour or so.

Yeah some of the books we went through its a wonder anyone stayed awake, even the conductor.
Some of the "explanations" of verse went on for pages. Then you were no wiser at the end.
The Revelation Book !! How many times did they have to study that?
Was it because it emphasised the "fact" that the Watchtower was Gods organisation etc.
They seem to make every verse in Revelation fit something the WT had done or was doing.

Another thing, the "group" was used to arrange the weeks field service for their territory.
How will they get round that? There will be a lot of running round at the KH telling members the arrangements

Also this will mean that there will be a "free" evening during the week.