While XV is a far superior experience to actually play, I'm going to go ahead and just say it:
For all the complaining about the Datalog and "fal'Cie" and "l'Cie," XIII had a much, much more coherent and fleshed out story besides a couple of sudden swings in character motivation.
Characters never got introduced and then completely dropped without explanation, though a few did get unsatisfyingly fridged.
It also had hours of actual cutscenes, like, with actual direction and cinematic flair, and multiple beautiful CGIs.
XV has, like, 3 CG scenes, while just off the top of my head XIII had at least 5 or 6.