As a Bard main who frequently does low level roulettes for some variety in my myth tome farming I can say that in many low level dungeons a DPS can easily take a few hits while a mob is being finished off, especially if the healer is on the ball, and usually, in low level dungeons, it's extremely easy for the healer to be on the ball. I also play WHM, and I can tell you from experience that healing low level dungeons is abysmally boring, I always enjoy a DPS that gets hit every now and then to spice things up, it helps a healer to prepare for lvl 50 content when they will have to be healing everyone frequently. I usually like to gauge a party in a low level dungeon, see how well the tank holds up to me, and how well the healer can keep up with the extra healing, if it's good on both, I just shoot away to my heart's content. If the healer has trouble keeping up, or the tank has freak out issues, I pull it back a bit. I'm currently working on my Warrior, and I know how frustrating it can be to have a DPS pull a mob off of you with that heart-stopping OMGISUCKWHATAMIDOINGWRONG feeling, but then I remember my time as a bard in low level dungeons and know that they can handle it for the last 30% or so of it's HP and move on to the next mob. Most DPS generally know that a boss is going to eat their face, but trash mobs are only mildly inconvenient when one is beating on you, and act accordingly, so trust them to know what they can handle and what they can't. Of course you do get some people who just never learn.