When most/all your GCDs are spent on DPS spells, in my opinion you are a DPSer. If you are almost primarily healing your party through oGCDs to me it is your secondary role to heal. I think it's just a difference in opinion though. I will agree that healer dps spells are just kind of there as there was no thought by SE in what to do with them so they just kinda tacked it on, made every healer dps the same with a different colored spell and moved on.