I'm afraid I don't agree.  From the action RPG gameplay, non-handholding game design and challenging difficulty, and unique online experience with messaging, co-op, and invasions (which I recall was one of the biggest praises of the original Demon's Souls), I feel that the Dark Souls series very much carries on the spirit of Demon's Souls, while also taking it into new directions with it's world/level design.

While I agree that Demon's Souls offered something different with its hub (although that sort of returned in DS2, along with a Maiden in Black-like NPC) and world tendencies (which I thought was a bit of a mess, requiring ridiculous things like staying offline just to avoid it affecting your game's world tendency), for me the core elements of Demon's Souls were it's challenging gameplay, online elements, and it's subtle lore/storytelling, which continued in the Dark Souls series.

Don't get me wrong, I absolutely love Demon's Souls (played through it several times while trying for the platinum), `I just don't see the appeal of creating a sequel to it when many of its elements are already existing in the Dark Souls series.  I'm personally hoping project beast is something fresh and different from all of the past Souls games, whether it's a change in setting (such as a shift towards a slightly more modern setting with early gunpowder weapons), online system, or some other manner.

Everything changes...

Path, enemies, loots, etc... even subosses.

The world tendency feature in Demon's Souls was nice in theory (i.e., the world changing based on your actions), but in practice, it often meant following a guide, playing offline, and doing silly things like repeatedly killing yourself to maintain/change tendency.  In contrast, Dark Souls 2 offers a change in the game on new game plus, with new enemies, boss encounter changes, new items, and so on.

I think that world tedencies are something that should NOT be brought back.
To be honest I feel it doesn't add anything to the game and it must be way harder for the devs to balance difficulty.

For instance, I never played as a human in Demon's souls so the w.t. was always white for me (I didn't do it on purpose, I didn't even know what w.t. was) so the game ended up being much more easy for me.