I believe it’s going to take three more books to finish the series.
Randland needs more words!
I read an article somewhere that I think Sanderson was following Jordon’s outline for the finish of the series which only was one more book. He decided to split and expand the end into three more (including the one just out) to get to the end.
I’m just glad someone picked it up to finish it. Two things I hate on serials (books or TV) is an unresolved ending because of cancellation or death, and second being continuing a series long past any reasonable amount.