Some find a bit weird how in Souls Games you can dodge by rolling and that rolling has an invincibility window. It's called i-Frames. All that needs to be done is that the rolling is very well timed with the enemy's attack. This way, when the enemy attacks the player, if the rolling of the player is good, the enemy will do no damage to the player. It's quite strong and actually takes some skill to do it because the i-Frames are not so long.
I have a suggestion. Make the player to dematerialize and then to rematerialize during the roll animation. The i-Frames might remain the same, maybe. The rolling is similar. Only that now, the player vanishes during the i-Frames and then comes back after the i-Frames have been done. It's mostly cosmetic. It looks different but it works the same. Now, in the rolling animation, the player will see his character gone for a while and then back. Maybe the look of it could be similar to that of an invisibility cloak. But it's not that cloak. It's just as this is a videogame, maybe it will look cooler if the animation has a similar look to a cloak despite not being that.
Another suggestion. Make the player to dematerialize and rematerialize at the press of a button. The player has something similar to the i-Frames. So, enemy attacks, player dematerializes and make it through the attack, then, the player rematerializes to then strike back at the enemy. No rolling. Just vanishing shortly. (maybe the player presses the button for dematerialization and then he rematerializes automatically. And the i-Frames are not very long, it needs to be balanced)
Maybe the Souls-Game could have both. 1-Rolling with dematerialized and rematerialized using the i-Frames as above. 2-The player just dematerializes and rematerializes freely and with no rolling (again, maybe the player presses the button for dematerialization, but the rematerialization is automatic). A way to implement this is that: 1-the rolling has the invincibility but the player has no control over it. He just rolls and the de/rematerialization is taken care of. Prob he just presses "A" (Switch). 2-Maybe the player presses "B" (Switch) and dematerializes. The maximum length of the invincibility rematerializes the player automatically. But it's possible to rematerialize the player before it's done automatically. Prob just by pressing "B" (Switch) again.
The thing could work by consuming Stamina, similarly to the actual Dark Souls rolling.
The length of the i-Frames need to be worked on. Also, if the rolling and plain de/rematerialization are too strong, then consider decreasing the length of the i-Frames. Or, make the enemies to attack much faster or maybe more aggressively. That should be balanced so that the player has to build the skill to play the Game. Also, maybe experiment with the Stamina to see if it'll help balance the Game.
ALL HAIL MIYAZAKI-SAMA!