We have no serious 70 druids here atm, so I'm going to speak out for the future druid community. I don't think druids should just get a DS as their defining custom spell. Not only because a 67 pnt DS will be basically useless with the amount of HP on custom mobs, but also because they have a better class-defining ability that'd be much more suited to be made custom. Here is the spell.
That defensive proc works, but the problem is that it doesn't proc too often atm. My suggestion is to give druids a custom version of that spell, and perhaps boost the proc rate up (it's probly 0, maybe make it 100?). In addition, I don't think a boost to the amount healed could hurt either since it's not effected by mods that the druid has.