I read you already made the choice to shaman but;
This. The way you heal with druids is up to you, because talent choices and secondary stats; you can make druid healing to your liking
You can totally make it so it's reactive healing and not pre-dotting.
You can use talents so that you put 2 rejuvs on dps and forget about them (they won't die no matter what, unless they actually kill them selves), or you can make it so that swiftmend has a more important role as reactive healing.
You can talent for better tank healing, for raid healing, and for M+, all with a lot of variety for your preferences. (Except raid healing, that one is pretty straight forward)