I'm having the same feeling as the OP. Well, I thought FFXV was... OK. Not terrible, just not really gripping.
FFXII, on the other hand, I've put in 15 hours in a few days and consider it possibly the best opening for a FF game. I love the early progression as well. Story pacing is great. A linear, interesting story, but with open areas and secrets to find. I never played it back in the day, so I'm really happy to get to experience it for the first time now, with the improvements/tweaks.
My ranking is something like:
FFIV = FFVI > FFVII > FFXII > FFIX > a bunch of other FF games with XV somewhere in the middle