I don't think that we will see another era of moderate southerner democrats. The Carter-Clinton period is definitely ended. Finally, we will see liberal northerners taking the control of the party.
The Democratic party will be a true progressive party.
To the contrary. As Democrats win Governorships and US Senate seats in the South -- offices often perceived as one election away from the Presidency, the likes of Lloyd Bentsen, Jimmy Carter, John Edwards, and Bill Clinton will return. Democrats can win in the South, but only as moderates. The Republican Party has become increasingly reactionary in the South, and it may be a matter of time.
I might not have a very high regard for the Presidencies of Carter and Clinton, but I can't deny Clinton's success in winning two landslide elections. That wasn't so long ago. The Religious Right has been weakening as a political force, and so far it can reliably deliver votes only in the South and the Plains states.