I think we can all agree that we don't like story content being cut from the main game so that it can be put in DLC or elsewhere, but I do like the premise of the FFXV Universe.
I like that by watching a movie, or a short anime series, or a novelization, you can enrich and expand what you know about the game's world and the characters within it. It's great that a lot of the XV Universe was released around the same time, barring the future DLC, so that you can have a multi platform experience.
Final Fantasy VII was released as a full game, and later on due to its popularity it spawned sequels and prequels in the form of a movie and other games. These didn't take away from the original game, and even expanded on things like the Turks and Zack's backstory. Whether or not you thought they were good, they did expand the story of the characters and world.
In the age of many properties getting multiverse style concepts attached to them, assuming the original game is intact, would you rather have a game Universe all at once within a few year period like XV? Or would you prefer the VII route of creating an expanded world years down the line?
Third option: Do you hate those and just want a game that's one and done? No expansion, just tell a good story and move on.