Along the lines that you suggest, Tolkien specifically address how he has
edited out specific "religious" content in LOTR, but nonetheless made the work
deeply religous in its underlying core message. He writes in Letter #142:
"The Lord of the Rings is of course a fundamentally religious and
Catholic work; unconsciously so at first, but consciously in the
revision. That is why I have not put in, or have cut out, practically all
references to anything like 'religon', to cults or practices, in the imaginary
world. For the religious element is absorbed into the story and the
symbolism."
Now the entire "religious" superstructure of Tolkien's legendarium is permeated
with aspects of his Catholic beliefs. What he does in the LOTR, however,
is avoid throwing in excessive references to his invented cosmology (Eru, the
Valar, etc.) because without having the Silmarillion as a point of reference,
readers wouldn't understand how Tolkien is creating a religious vision that,
while it looks like a fantastical--"pagan" would be another appropriate word
for it--set of myths and legends, is fundamentally in line with Catholic
Christian beliefs. It would simply be too complicated to explain the
parallelisms, and readers would be distracted in the end from the basic themes
of pity, compassion, redemption, etc., that make LOTR a deeply moral and
religious work in its essence. True, Frodo is not a "Christ-figure" and
neither is the resurrected Gandalf the White, but both embody the same moral
truths as the Christian tradition and typify deeply Christ-like ideals.
Keeping it simple like that avoids having to spend pages explaining that Eru
Iluvatar is ultimately another manifestation or mode of perceiving the
Judeo-Christian
God.
Still round the corner there may wait
A new road or a secret gate;
And though I oft have passed them by,
A day will come at last when I
Shall take the hidden paths that run
West of the Moon, East of the Sun.
