Matt Nickolas Herzog, I have to answer here cause I cannot click reply on your reply for some reason.
Something that has helped me a lot with the bosses in the DLCs was changing how I roll. I used to roll at the startup on the Boss attacks in the vanilla game, but the DLC bosses have a tendency to delay their attacks, so try to roll at the last possible second. Also having a lot of Adaptability (for Agility) helps with the i-Frames of your rolls.
Also, generally try to roll into the attack and not away from it, otherwise you will get hit. Best example for this in the DLC is Aava from the Ivory King DLC, a very hard boss but by rolling into the direction where his paws come from it gets a lot easier.
Hope this helps a bit
I sit my back agents the wall. My own blood drips onto the floor. My hands are shaking barley able to grip my broken sword. My shield shatter lays on the floor. This monster that stands before my has slain hundreds of warriors more skilled then i. Yet i steel my self for i refuses to sit hear and die. If it wants to feast on me. i will make it fight fore its own life.