Almost everyone thought that it will be 15th, but now it starts to look unlikely. Time between seasons has been very small last 2 seasons but now 22th looks sadly more likely. Maybe they have problems with blizzcon PTR changes. There was so many changes but so small time to test.
It's pretty safe to say that season will start next week Friday (Nov 22). This week would be too early with no heads-up anymore (basically patch would already be live on the US as patch day is usually on Tuesday) - and the week after it's Black Friday. But we don't know for sure.