They're improving content and not fixing anything. Fixing is meant for broken things and there's nothing broken here. They mentioned Ravus who is a side character, he doesn't have much presence in the game but the game does explain some of the happenings around him if you actually listen and explore(they talk about him and certain events about what happened when the city was attacked on radios for example. Not the best way to do things, I know). So they're probably going to make those into custscenes now. Ravus' ending does leave a lot to be desired though but again, he is a side character. The story focuses on Noctis and his gang and it delivers on that part, immensely, but at the cost of side characters like Ravus losing attention(part of their stories are often told by the news on radios, including a bit of Luna's).
Then again, Tabata still deserves criticism for his approach to the story of FFXV. Kingsglaive and Brotherhood SHOULD HAVE BEEN in the game. I commend his dedication to improving FFXV but his ideas and approach are just often questionable. It's apparent he thought FFXV will be perfect - he said FFXV will be the highest rated FF game of all time which means he thought all the problems in his version of FFXV's story are actually great things.
Anyway, I hope if Tabata ever returns to an FF game, he just focuses on the gameplay aspect as he excels on that department. FFXV is amazing in gameplay and content but is a bit lacking in story, even more so if you haven't watched Kingsglaive or brotherhood.
