Even if you want to play smart as DPS, unfortunately it's not "rewarded," as many people judge DPS based on the numbers from addOns like Recount. Thus you don't get points for holding back so the tank can grab or regain aggro; you don't get points for interrupting your damage dealing to turn around and help rescue a healer that's drawn aggro; and unless I'm misunderstanding, you just don't get points for having a play-style that varies from pure damage dealing.

At least in battlegrounds, honor is calculated to include how close you fought on a flag, in addition to your kills, damage, and healing. It would be interesting to see if a more nuanced calculation other than pure DPS would affect how people play their DPS.

Btw, I play hybrid, since I solo-leveled to 70 before getting involved in PvP or instances, and that playstyle has "stuck" for me on my main, even though I'm technically DPS. That means when I got into a PvP skirmish with a priest and a warrior on my side, and the priest wasn't throwing heals, I was fine stepping back from the fight to throw the warrior heals to keep them in the fight. My alt however is pure DPS, and that difference is making me appreciate the versatility and survivability of a hybrid. I'm planning to dual-spec as a healer on my main, so I'll get to walk in those shoes soon and see how I feel about that.