I've not played DeS
1) Dark Souls
2) Dark Souls 3
3) Dark Souls 2 (best PVP, everyone loves hating on it because memes.)
4) Bloodborne (Great setting/story but dat 30 fps)
I pretty much agree with this. I just think the world is more cohesive in DS, and had better boss fights. I'd give DS 10/10, it is a masterpiece in every department. I do miss the more user friendly parry and riposte too.
DS3 gets a 10/10 too, based on current games on the market.
DS2 is better then most action RPGs too, and gets a 9.
Demon Souls is also a 10, immense in every department, but like DS3 the level design as in cohesive world building isn't as good as DS.
Bloodbourne has great fluid gameplay, interesting NPCs and story, and awesome bosses along with a creepy lineup of enemies and a very creepy ambience, a 10 too.
As you can see, it is very hard to decide which one is best, because everyone of them has some better aspect then another.
Suffice to say, From Software are the best action RPG development team, like ever imo.