It wouldn't work, Dark Souls is designed for that difficulty, add an easy mode and you ruin the balance of the game. On all other games difficulty is an option, on Dark Souls it's an integral feature of the game, that adds up on the atmosphere, the setting, the game design, everything. You can't just add an easy mode in Dark souls without breaking what is actually a Souls game.
What about Guitar Hero?
That always had difficulties, and the guitar that came with it had 5 frets, which only really come into play on the hardest difficulty.
The games were clearly designed to be played on expert, but players were given a choice, even if it sacrificed some of their vision to allow them to enjoy it.
I know Souls is a different game, as is almost everything else, but you could realistically put easier difficulties on most titles, Souls games included.
Ruining the balance of the game is entirely the point of an easy difficulty though.
I feel like the best way to please fans who are extremely against an easier difficulty is to do it Streets of Rage 3 style, and finish the game prematurely, and encourage players to take what they've learnt and go through on the original difficulty. Like, end Dark Souls easy mode after Sen's, and maybe restrict access to the Catacombs as well.
