I really don't get the people, who are disappointed there was no GTAV main story DLC or expansion. What was it they originally planned, something with Trevor as an officer? If you want to see the main characters, some of them actually appear in GTA Online. There is story content with Lamar, Franklin, Trevor, Lester and Ron, on top of tons of new characters introduced with tons of new story content. There is an entire heist with Trevor. That is probably more than you would have ever gotten in any DLC or expansion.
The entirety of the Doomsday Heist together with the ULP follow-up where you go back into Mount Chilliad, and you have to see Avon's cyborgs is some of the funniest and most interesting story and gameplay I've seen in video games in general.
And you all get that for free in GTA Online. For singleplayer DLC or an expansion you probably would have had to pay.
I'm glad they keep adding content to GTA Online, which I can play for free, But somehow they force you to spend your life savings on shark cards, even though they shove money up your ass at every opportunity.