Something tells me they want to polish this beyond expectations
You don't know them very good.
Given what we seen on Tribble, there is no way they are going to polish so much they will hold off for a few months. It's just more rehash of the same pattern: new season with a few new storyline missions, an adventure zone, a new reputation and a new fleet holding to keep us busy until the next season, which players will burn out the content within 1 month.
But due to the winter event, people will be extra burnt out because they have to grind the Winter Event for new clothes.
21st is probably about right but I will say tuesday the 19th.
The often launch seasonal updates early in the week. Geko said the FE will run for about 2 weeks and that gives them a few extra days to get ready, and the christmas event usually starts fairly early in December.
They always try to get the Seasons out to take advantage of the Holiday break. That's just good business: strike when the most people are available.
STO is about my Liberated Borg Federation Captain with his Breen 1st Officer, Jem'Hadar Tactical Officer, Liberated Borg Engineering Officer, Android Ops Officer, Photonic Science Officer, Gorn Science Officer, and Reman Medical Officer jumping into their Jem'Hadar Carrier and flying off to do missions for the new Romulan Empire. But for some players allowing a T5 Connie to be used breaks the canon in the game.