Talking about TS6, I hope she'd release it in 2017. 1989 is arguably her biggest era, I can see she still can push it further. If WD became a hit, she can push two more single (OOTW for Winter / New Romantic for Post-Holiday and Valentine please).
Then she can release 1989 Platinum Edition with deluxe tracks plus one-two new songs, promote one single to sell the album, then go silent while finishing her biggest tour to date.