Hello, I'm the minority that prefers KH even for its story.
I feel like no one is taking into account how long it takes for the story to get good in FFXIV. I've heard Shadowbringers has a good story, but I played FFXIV until mid-Heavensward and found it to be such a slog. There were almost no interesting plot points and when it seemed like it might get interesting, the game threw so much filler at me (which was apparently improved in a patch way after I quit). Remember that one time you were asked to go gather ingredients for a banquet before going to beat a boss? That took hours. No single world's substory in KH takes that long, which for me, gives it the win by default.
I can't compare any further than mid-Heavensward, but from what I've played, the beginning of the KH saga was much better than the beginning of FFXIV:
- KH1 has a way better story than A Realm Reborn
- The beginning of KH2 is way more interesting than the beginning of Heavensward
Lastly, for the dialogue, I slightly prefer KH's slow talking and cringy use of words like "hurt", "heart", "light", "darkness" (coming soon: "unreality") every sentence over FFXIV's long-winded dialogue. In a game that is already so long, they decided to make it even longer by adding a ton of dialogue about nothing. You could remove 90% of the fluff in dialogue, even in more important scenes, and nothing of value would be lost -- the gist of the story would probably be easier to get, too. Again, this is just based on what I've played -- it's possible that this gets better after mid-Heavensward too.