In a lot of cases it’s almost better if a show gets an early renewal before the season has even premiered so that the creative team can start looking ahead to the next season.
So, it looks like there are some creative considerations as well as practical considerations related to why Katrina: American Crime Story will not be hitting the schedule at all in 2017.
It takes a long time to write, then shoot and then go through the whole post-production process for a series.
It’s not super weird for the show to be skipping a full season.