I have 'peeked' some gameplays (I will only get my copy at the week-end :(.. and I just can't wait to experience it). And from what I've seen, I think I will enjoy this game. There are some let-downs for sure, but then in the past I also couldn't be able to 100% liking FFVII, or any other FF games. I can't even remember half of the stories of each every FF games that I've played (I to X).
Watching FFXV gameplays had me remember why I was so immersed to this series during my childhood-teenage days. It's not about the story (as I said I hardly remember the stories). But the magical journey, the otherworldly experience, the dedication to the aesthetic, and the wtf moments like when you first saw Diamond Weapon in VII or summoning Odin in VIII. I found it all again in this game.
Ofc it's pretty subjective. I won't argue with that. Even between FF fans they are arguing each other which FF is the best or which was the reason of the series decline. Everyone have their own preferences and for me FFXV (and many other FF games) just suits my gaming taste.
Therefore, I don't really care with the score (in the way, low score will make me don't want to play the game & vice versa). As from what I've seen, I'd score this game 85 at max - mainly for the effort to make such an ambitious game. PS4 surely can't handle how FFXV was first envisioned. There are so many ambitious scenes / gameplays in that one-two hours clip that I watched. In five years, maybe there will be a remake for this game, when VR system will be more advanced - since that's how this game should be played and can be experienced better. Fighting a raging Leviathan that's destroying a city in a whirlwind on a more advanced VR system would be amazing - not just in 'press a button to continue' cut-scenes.
Imo, FFXV won't mark the series decline. It will mark good things to come in FFXVI. Well hopefully with better, more captivating storyline next time.