I really don't thing the Witlesses are going away. Too many people have invested too much time... I take that back I dont' think they are going away anytime soon... However if they plan to stick around they must change soon so what beliefs will be jettisoned this week as the light grows brighter and what beliefs will they keep (and why)
1st obviously is that the GB is only one step (small step) below god and at least equal if now one step above Jesus
Jesus is gods son (this one is supported fairly well by the scrips so that's an easy one to keep)
Jehovah is gods name (this is becoming more a mainstream belief so thats an easy one)
Earth will be a paridise and people will be resurected here... this is hard if they change their end times destruction message then when are people resurected? If they tell members you are going to die in this system how many will continue to serve? They may have to adjust that slightly...
I'll see if I can think of a few more!! Post away though!