Honestly speaking, I don't think the primary goal of the current healer design is for it to be fun and engaging for the healer player at all. If you look at the design from that perspective, the design is incredibly bad and makes little sense.
However, if you look at the design from the perspective of one that's being healed, everything makes sense. The simplified damage kit is so that the healer will make sure that you never die, they're always available to top you up from your mistakes, their bloated OGCD kits make it so they always have a way to fix mistakes made by you or others, etc.