The cast really seem to be very close to Lynch though and it looked like they wouldn't return if he didn't. They all felt that he added "something more". Often unexpected things beyond the script.
But as some suspected, negotiations continued and a previously reliable source hinted today that Lynch might be back. Rumors of course but I wouldn't be too surprised.
I don't mind other directors either actually. In a way Twin Peaks is what it is due to different vibes. And Frost is also there after all. It just would be nice with a couple of episodes directed by Lynch. Or at least him being there to keep things from straying too far from his and Frost's vision.