Played FF15 a little.
My feelings on this are very similar to my feelings on Nier Automata. Both games want to be systemic and narrative-driven at the same time. FF15 obviously had millions of moneys thrown at it so it has bigger world, more diverse enemies, more NPCs and more of everything. So at least you don't get bored of fighting the same types of enemies. I also feel that combat system is much more involving while still far from tactical combat I'd wanted. Nier world difficulty is tied to story progression and it's almost impossible to meet anyone you couldn't beat with autoattack (at least on default difficulty level), plus the enemies in Nier are more homogenous and there's just fewer things you can do in combat. Slashing and shooting the shooty thing was enough for everything I've encountered. In FF15 I can venture into zones beyond my level and get something good from there. In a manner reminding me of Might & Magic you have to plan your trips around the length of your food buff and where you end up spending money on rest which multiplies acquired XP. Economy works, you need money to buy ingridients for said buffs (and also for spell crafting) and monsters don't drop money, you have incentive to do sidequests.
But then again they're similar in progression system. Everything interesting and useful you can get in first few hours of the game. In Niear automatic use of item (it's even more effective than using items yourself!) effectively makes you immortal outside of random 1-hit kills, then you get some vampirism, counter, maybe some defense... And after 1/6 of the game you don't really want to add anything to your repertoire. In FF15 there are more of various abilities, mostly in teamwork and combat Skyrim skilltrees, other skills trees offer some cheap abilities that are little helpful... And after that when I look at those skills I see hours of grind for some dubious benefits. The only thing I care still (chapter 7, shortly after the photo with the princess) are stat boosting skills (they cost 99 AP and give you +1thing/level), there are 5 of them and I already got 2. Everything else is meh. This makes all the systemic feel of the game crumble.
Sidequests are designed to be something you engage in on your way somewhere or purely out of greed. In a good RPG I grind with a feeling of joy, it's like lifting weights knowing that you'll be able to lift more in a short while. In Final Fantasy 9 I grind for AP to learn that thing from an item and switch to another item getting access to an interesting ability. In games with job systems I grind to make supersoldiers with all kinds of abilities. You don't need sidequests to force me to grind, it's not a chore, it's a joy. But here once I have enough money sidequests feel redundant. Yeah, the game throws at me giant monsters from time to time reminding me that there's plenty of growth to do still, but I know there won't be much interesting in that growth. Don't even think those relics I find make for more interesting builds. Only the biggest hunts give you a challenge, sometimes it makes sense to run away, get specific spells and eat specific buffs and return. Well, at least this game has a better Witcher gameplay than Witcher 3 did.