Jeph Loeb says that they may be back but with a new lineup:
Marvel's Jeph Loeb Hints at Defenders Return With Potential New Team - IGN
If they have a new lineup, it's Colleen, Misty....maybe Trish Walker and...........maybe Punisher?
Looking at the list of Defenders from the comics on Wikipedia and most of them are in the movies and those two will never cross each other.
The Shadowland story would be ideal for a second Defneders series, and would warrant a full 13 eps rather than 8. ..... Bring in some more characters in Heroes For Hire first and have a bigger but looser collection of "Defenders"
Luke Cage
Iron Fist
Misty Knight
Colleen Wing
Jessica Jones
... and then add Hellcat, Shan-Chi and maybe Paladin.
Have Daredevil as the villain following the comic story and White Tiger among his henchmen and throw in appearances from Punisher and towards the end Elektra.