Real talk - top to bottom I think Dark Souls 3 has the best levels in the franchise.
DS1 still ace. Sen, Blightown, Catacombs. Even levels like Amala in 2 are better than most areas in 3.
My problem with 3 levels is the gray palette in the first half and the lack of environmental hazards. A lot of areas felt kinda straightforward in their approach, basically a lot of big rooms in which you kill stuff.