I hesitate to say that the Souls series has "superior" combat over DD. I think they're both excellent. Sometimes you just want to be able to jump on a monster's face and slash it to death. Not every game would benefit from Souls' deliberate, careful pace.
it's not really a contest IMO. forget deliberate pacing.
Bow combat in DS is better. I don't need to be a magic archer to lock on, and i can perma-enchant any bow.
Shield based combat incorporates the parry/riposte counter- meaning you can really put the hurt on mobs if you're good enough.
Knives (and certain shortswords) allow you to backstab in DS. Again, takes skill and some timing but a hell of a bonus if you're good at it.
The "poise" stat in DS allows you to take heavier hits without staggering, should you choose to raise it.
There's more of a sense of "weight" to weapons in the souls series. Not sure how to quantify this one. Heavy weapons are noticeably tougher to wield.
Dark souls in particular does a good job with balancing stamina cost of weapon use, vs. running and defending. You can swing that greatsword, but don't try to absorb a strong hit right afterwards- it'll backfire on you something fierce. Edit: I played through most of my game as a magic archer/ranger. I had knives, but couldn't block unless i was a shield class? kind of strange. DS allows you to block with anything- it just won't be as EFFICIENT as with a shield.
Magic based combat isn't really even a debate. Defensive and Offensive magic is more extensive and better thought out- falling not just into "attack" and "healing" but faith based vs. sorcery, and dark souls has pyromancy- so even non int/faith builds can get in on the action.
And that doesn't even get into the weapon customization, which is again flat out better. I can upgrade ANY weapon to flame based, thunder based, faith based, to scale with strength, intelligence...
it's not close at all.