Mesmer with healing power
It’s probably not worth stacking healing power in that build. According to the GW2 Wiki, Restorative Mantras heal for 2600 + 0.2 * healing power, so you don’t get much extra value from the healing power. It might be just about worthwhile if you used a full set of runes of Dwayna, because this will cause you to proc AoE regeneration, but for that to work, you’d need to use Mantra of Healing. Even then, I think you’d be better off stacking P/V/T gear for defense and using staff and sword/focus.