[Raynor]

Here is the quote concerning the legacy Tolkien left for others to complete his work (well, he at least intended that initially):

Originally Posted by Letter #131

I would draw some of the great tales in fullness, and leave many only placed in the scheme, and sketched. The cycles should be linked to a majestic whole, and yet leave scope for other minds and hands, wielding paint and music and drama.

More wordly and better educated

Then again, Tolkien did note (and perhaps regret) the difference between his two works

Originally Posted by Letter #125

After all the understanding was that you would welcome a sequel to The Hobbit, and this work can not be regarded as such in any practical sense, or in the matter of atmosphere, tone, or audience addressed.

Originally Posted by Letter #131

The generally different tone and style of The Hobbit is due, in point of genesis, to it being taken by me as a matter from the great cycle susceptible of treatment as a 'fairy-story', for children. Some of the details of tone and treatment are, I now think, even on that basis, mistaken. But I should not wish to change much. For in effect this is a study of simple ordinary man, neither artistic nor noble and heroic (but not without the undeveloped seeds of these things) against a high setting — and in fact (as a critic has perceived) the tone and style change with the Hobbit's development, passing from fairy-tale to the noble and high and relapsing with the return.

But still a Hobbit and subject to the flaws of a Hobbit's interpetation of matters beyond his experience.

If I interpret the LotR Prologue correctly, LotR is actually an improved Thain's Book, (itself a copy after the Red Book kept at the Undertowers, the home of the Fairbairns, Wardens of the Westmarch, and it received "many corrections" in Gondor. These corrections probably eliminated the inconsistencies that appeared due to the peculiar skill (or lack thereof) of the hobbits in writting down the events. I would also note that in Letter #168 the following meaning of Frodo is given:

Frodo is a real name from the Germanic tradition. Its Old English form was Froda. Its obvious connexion is with the old word frod meaning etymologically 'wise by experience', but it had mythological connexions with legends of the Golden Age in the North.

Of Merry we know that he also received wisdom from his experience with evil:

Originally Posted by The houses of healing, RotK

But these evils can be amended, so strong and gay a spirit is in him. His grief he will not forget; but it will not darken his heart, it will teach him wisdom.

So, all in all, Frodo's more terrible experiences, the bearing of the ring, and the wound he received, helped him mature more quickly, and write a better work at an earlier age than Bilbo:

Originally Posted by Letter #153

Suffering and experience (and possibly the Ring itself) gave Frodo more insight; and you will read in Ch. I of Book VI the words to Sam.

So I suppose he would not bother even speculating who/what Tom was: likely he thought it unnecessary.

He did question Goldberry about who Tom is, although her answer, "he is", left many people wondering whether Tom is Eru, but Tolkien rejected this particular idea firmly:

Originally Posted by Letter #153

[Peter Hastings cited the description of Bombadil by Goldberry: 'He is.' Hastings said that this seemed to imply that Bombadil was God. ]
...
As for Tom Bombadil, I really do think you are being too serious, besides missing the point.