I haven't seen the finale yet. I assume the vampires will not permanently be able to stay in the sunlight. Otherwise, it wouldn't make much sense that Lillith was able to die from sunlight after drinking Warlowe's blood millenia ago.
Well, that's True Blood for you. None of it ever makes any sense, and trying to make sense of it is pointless. Yes, the way that Warlow dying made every day vampire lose their powers probably means Lilith never should have died from the sun, but that doesn't matter.
This was a terrible finale and really nothing of consequence really even happened this season:
Warlow's gonna come get you! Oh, but he's nice. But no he's not! Oh he's dead now, the end.
Bill is a super vampire! He can't be killed and has super powers. He does little with these powers. He loses these powers and is back to normal.
Alcide is now a pack master. And now he's really mean! Oops, he's not pack master anymore, and is right back to where he was.
And the worst roll eye moment was Tara and her mom. Just terrible writing.