Hey Walk!
The anachrony of the Valar power is not stated because they are not Physically in middle earth, it's because they decided that they will no longer intervene in the events occuring in Middle Earth, that's the work of the Istari.
About Lúthien, if she were a "normal elf" I could accept that, but she is a mortal one. She decided to come back to life with the condition that she would leave the world when her short life was over. Having them reincarnating, even as a ghost of a mortal being, which in Tolkien is usually related with evil corruption, is really out of place. (I would not enter in the overuse of magic in Imladris, I promise
)
Speaking about councils, I think that it is more plausible that some people meet in Rivendell to speak, like in the Council of Elrond than making the Valar change their mind for blowing some goblins or any of the other anachronisms.
That was the lore discussion, now:
Yes, a generic spell is kind of bland, that's the reason for putting it in a specific mechanic. I know that if the team has come up with another mechanic, that decision is now, mostly, set in stone, and now it's strange to speak about suggestions here. The council will not be in the spellbook but I would love to see the generic healing spell with a little bit more of personality, the sanctuaries being an option.