Well you don't need to dps in normal groups but let me tell you in Savage (you mentioned this raid so imma talk about it) you're going to want to dps because you're going to get so tired of not meeting the enrage and dying with 1% hp remaining on the boss. After so many wipes at 1% you just want to clear by any means at that point. Still though even in savage as a whm you're still healing 98% of the time, the healing requirement in Savage is no joke either