The changes boil down to the following:
- Ability to read from the chat panel (with filter support)
- Ability to access fellowship member vitals (no raid support yet)
- Ability to access the context menu from the player portrait
- Ability to access the items that the player currently has equipped
- Ability to create a new element that works like an equipment slot
If I'm correct, and effect information is available for fellowship members, and writ of health produces an effect, that should be possible. if either one of those are false - it would be difficult to pull off reliably.