Revisiting the physick question

[Mhaeric]

and there is no way [RDM] can replace a healer in any encounter just with his verraise and vercure.

This is patently false. In most content outside savage content and 24-man, a RDM is more than capable at healing. To the point that if you have a preformed, it's actually a viable strategy to do dungeons as Tank, RDM, DPS DPS. It'll be a lot busier than as a healer, but it's more than possible to do. E.g. I've healed the vault's final boss as a RDM when the newbie WHM fell apart the first two attempts. After they died yet again before the boss's ultimate, I just switched over to main heal and finished up the fight for them. It was full of clutch moments, for sure, but it's definitely doable and there isn't really any other fight that requires as much healing as that one in normal content.

That said, I don't advocate being a RDM that heals on the side to 'help' the healer. If a healer is there let them do their job and focus on what you're there for which is dps. If the healer dies, or your preformed chose to not bring one along then go ahead and heal away.