GTA VI seems very far away from now. How about a DLC to V
Angels of Death. Once the kings of motorcycle world, Today, rusted and torn apart after years of being at war with their worse rivals, The Lost. Now, a truce with The Lost has protected their way of life. As The Angels of Death drug enforcer (insert protagonist's name here) must get his gang back in the meth business. Blaine County has all the open opportunities but a truce with The Lost can't be broken. The Lost President, Johnny Klebitz is deteriorating himself and the chapter with the overuse of the very same drug he sells. Will this be the way to get back in business or must a truce stay unbroken?
I really like the idea of an episode DLC, it worked out very well in GTA IV and I think they could still make it work in V. BUT I think if we just keep adding characters it will get a bit hectic, but there is one solid chance at a episode (beside the fact they said they won't be making any)
Franklin after the story. I see two things happening. Franklin forgets about Trevor and Micheal, or is done associating with them and goes back to the 'gangster' life. He's back in the Families and is now loyal to them with the mindset of getting them to the top again. Or Trevor and Micheal are either dead or gone, and Franklin continues to to heists with Lester's help and everybody he's met throughout the story. Then somebody like Patrick could become more involved, maybe even the Lost? Characters that were already introduced and in the game could become Franklin's new 'team mates' in the new story.