I'm extremely late to the series, as Remastered fixed what broke my experience of the first game. Playing SoTFS now, and I'd say Dark Souls 2 combined taking some good notes from Dark Souls, while having less insight into some concepts.
Areas in the DLC demonstrate it best (e.g. Iron Passage, Frigid Outskirts), where powerful enemies that wouldn't have respawned in the original, do respawn now. The iron knight guys with flaming shoulders are a fun challenge at first.... but as a constant obstacle they kill the flow of the game.
There's nothing wrong with dying, and challenge. But some challenges are only fun to overcome a single time. A bonfire near to the boss OR no respawns for particular enemies, woulda fixed this.