I felt that Warrior gave the smoothest transition however, there are skills from both you will want. By the time you get your cross-action skills, you will be fine just picking up Drk and going with it. I did and did just fine. As a matter of fact, I notice that I play better than 90% of the Drks in DF and some of them have other tanks at 60 and Drk is my only 60 tank. Don't let elitist trolls discourage you.

Awareness is not required. It can help mostly for my Warrior but I've never been in a situation where I thought "wow, I'm glad I had that!"