Inconsistencies

[CSteefel]

Originally Posted by The Mouth of Sauron

- Gandalf released Shadowfax in Eriador two months before the Company left Rivendell, but Eomer told Aragorn that the horse had returned to Rohan only 7 days before they met in the Wold.

Shadowfax presumably took his time, and there was no reason for him to return to Rohan except for the purposes of meeting Gandalf. That is about when Gandalf made his way into that region.

Originally Posted by The Mouth of Sauron

- Denethor and Saruman both encountered Sauron using their respective Palantir. Yet Denethor was not dominated and Saruman was. Surely it should have been the other way round ?

Paradoxically it seems, Denethor was the man with the superior will power. Perhaps also the right to use the Palantir was part of it as well.

Originally Posted by The Mouth of Sauron

- What was the point of Eowyn dressing up as Dernhelm ? Surely the sight of a hobbit sitting on her horse with her would have given her away anyway ? Same goes for the scene in the film before the Riders charge at the Pelennor.

My understanding was that he hid under her cloak, although clearly some knew they were there.

Originally Posted by The Mouth of Sauron

- If Gwaihir could fly to Mount Doom in a matter of minutes, why not just give him the Ring and ask him to fly down there and drop it in the volcano ?

See comments in the recent thread on Eagles. My interpretation is that the Eagles in fact are the agents of Eru and they were prohibited from intervening directly in the destruction of the Ring. Otherwise, as you said, a lightning strike into Mordor and Mount Doom could have taken care of it.