Sure if you are talking about trails or raids its easy cake for most part as a tank, but not in other duties. DPS stressful, in savage raid maybe, but not in other content, your death does not wipe the party, you are not being pressured if you do a mistake, and "rotation difficulty" is just a job aspect that everybody could get used to when play long enough and train muscle memory. If you do something wrong as a tank then everybody pays for it.
You could literally wipe entire alliance raid if you position the big boss in the wrong spot, and you could easily die when pulling big, have to adjust and rotate your CDs so you are always having some form of mitigation in order to let you survive otherwise healers wont be able to heal you from it.
You thinking DPS is stressful is only you trying to get the good dps number and kill stuff fast, if you screw something up it does not cost a wipe, barely anyone cares outside of extreme and savage content if you die. If you happen to tank and someone dies because you positioned something wrong then its all on you, same with healers they are resposinble for death of the party even more.