I dont know why people say gnb is difficult or distracting. It's real problem is lackluster mitigation which is why I never liked it. If you want to learn the tanking role I'd recommend WAR. You start at level 1, will ease into the role and the job basically keeps getting better the more you level whereas paladin becomes a lot more strict in its rotation and bloats your action bars with garbage like cover. DRK Is ok but doesn't get good until 72 so that's a deal breaker for a lot of people.