Defects in LotR ? (Gasp)

[Turambar]

From the Prologue to Lord of the Rings:

The most critical reader of all, myself, now finds many defects, minor and major, but being fortunately under no obligation either to review the book or to write it again, he will pass over these in silence, except one that has been noted by others: the book is too short.

I wonder what defects, major or minor, Tolkien found in his great novel? Major defects, I can't imagine (maybe that gay subtext. [img]smilies/evil.gif[/img] ) Minor defects would, I guess, be little glitches or inconsistencies that he found on re-reading. I always thought it was odd when, on Weathertop, Strider stops Frodo from telling the tale of Gil-galad:

I know only the little that Gandalf has told me, - said Frodo slowly. Gil-galad was the last of the great Elf-kings of Middle-earth. Gil-galad is Starlight in their tongue. With Elendil, the Elf-friend, he went to the land of...
- No! - said Strider interrupting, - I do not think that tale should be told now with the servants of the Enemy at hand.

And Strider seems especially concerned that Frodo not say the name "Mordor". So Strider instead tells part of the tale of Luthien and Beren, and within 5 minutes mentions Mordor and Sauron, and refers to Morgoth himself! Maybe this is exlainable, but I always found it strange.

Any guesses on what defects, major or minor, JRRT saw in his own work?