While I certainly like having healing handy, I don't tend to view it as requisite. Plus Spirit has at least two options that are just as good or better than healing. You can use Fortune or Fate to bring a hero back if they die. Or Frodo can simply take damage as threat and hence never needs to be healed - I prefer this to healing, especially if you have threat reduction to back it up.
In the end the argument between Lore and Spirit is probably not necessary. They have numerous high impact 2 card combos that cross the sphere boundary that they are a great pair of spheres to play together. Fast Hitch/Frodo, Asfaloth/Glorfindel, UC/Beravor, Hammersmith/Mathom, and Ziggy/Gildor. come to mind off the top of my head.