Depending on your ending Devin, Stretch and Haines can all be dead so I doubt they'll be explored. Since any of your characters can end up dead I assume expansions won't involve them either. Most likely an expansion will be set around more or less completely new characters.
Thoughts on the ending?
I thought it was a bit of a disappointment on the whole. It didn't feel like there was a common thread or plot arc really, more a series of unconnected missions that just suddenly end, particularly compared to San Andreas and GTA IV.
Hope that doesn't need spoilering, it's pretty non-specific.
I can see plenty of scope for the inevitable expansions to elaborate on things though - particularly stuff like Devin vs Solomon, or Lamar vs Stretch (do we ever even meet Stretch? I can't recall). I think there's plenty of scope to delve more into the Steve Haines/ Dave stuff as well.
There's a fair few characters as well that never seem to get much screentime, despite being introduced in a big way. After maybe one or two missions where they are established as being fairly major supporting characters in the three protagonists' backstories, they almost immediately fade into the background aside from the occasional brief phone conversation (Patricia, Chef, Wei Cheng and even Lamar).
Edited by darkmorgado at 01:53:15 06-10-2013
In terms of my thoughts on the ending I haven't seen them all yet and I don't think the story as a whole was as strong as some of Rockstar's other output, but I think the delivery was by far the strongest of their open world games as by having lots of different characters and story threads it all felt relevant, compared to in GTA 4 or Red Dead where the story was more focussed but in order to make the game long there was a lot of what I would consider to be padding, which lessened the impact imo.
Edited by Stranded87 at 15:30:25 06-10-2013