Four months of contestants like last year
I think BB could ruin its chance of survival if they get too greedy. It is also an awful long time to expect people to be away from their loved ones. They would also have to make the house a lot larger, there is no way 20 people could live in a house the size of the present one. Perhaps they are hoping to provoke more arguments which would be likely with this number.
I too much prefer it when you get to a lower number of people; you get to know them much better and most of the falseness put on at the beginning has gone and they are more or less being themselves.
So a 4 month BB has thumbs down from me.