It was suggested in the past in a different thread by someone and I'll restate their comment here:

It would be nice if you got a MND bonus for having a single healer and both a MND and PIE bonus for having two healers.

This is pretty much a compromise on your first suggestion but I liked the idea enough to re- introduce it here.

Overall i do think party stat bonus should be adjusted as a small balance change to the healer meta.