I think 4e (and D&D in general) would be a woeful mismatch to LoTR; much as MERP was (I played lots of MERP years ago and it was a great game but a poor window for exploring Tolkien's worlds). D&D is almost the anti-thesis of Tolkien; Gygax HATED Tolkien and was a fan of pulp Fantasy and only put in Halflings etc under pressure from fans and friends.
Magic is a passive and largely mystical thing in LotR, and even evil magic is quite subtle. Take the three Elven rings; Narya, Nenya and Vilya. Gandalf actually has the Ring of Fire; Narya but when do we actually ever see him use fire -magic? In the films; never, but in the books he uses it exactly twice. Once to light a camp fire as the Fellowship retreats from the avalanche at the path of Caradhras and once to set fire to Worgs in the Hobbit. This ring though, is how Tolkien implies that Gandalf overcomes the Balrog, because its fire cannot harm him (that and the fact that Gandalf and the Balrog are essentially the same race; i.e. Maiar or servants of the Valar).
Similarly, the fact that Rivendell and Lorien are outside of "normal time and space" and are hard to find and somehow imbued with the glory of a past age of the world is down to the fact that Elrond is keeper of Vilya and Galadriel of Nenya. Both of these ring's only true power is in the preservation of the feeling of the energy of the world when it was young, before the coming of men. So magic in Tolkien is like fine art and is a reflection of the nature of the world.
I agree there is nothing in any RPG that strictly prevents use of it to depict it Middle earth, but to put Tolkien's world into the same frame as fireballs and instant magic is like trying to marry a cartoon with the works of Michaelangelo.
So to make it work we would have to drop nearly all "magic".
Similarly, with Martial characters, there is a serious mismatch that would require re-jigging the XP system; because both 3E and 4E reward killing monsters and this is the very opposite feel of what you want to achieve in a game based on LotR. Take Frodo; he refuses to kill Gollum, as does Bilbo before him, purely out of compassion. We are also told that the great Gondorian warriors of Old only took up the sword to defend what they loved and that only orcs delight in slaughter. This is a central theme of all Tolkien's works and to ignore it is to fail to truly come to grips with him and his world.
To make the game reflect LotR you would need give all XP via quests and make each creature killed SUBTRACT from the final XP awarded. Then players would start to behave Heroically (in the sense Tolkien would have understood) in order to maintain an LotR feel.
The closest match to LotR I have seen for an RPG "out of the box" is Decipher's Lord of the Rings RPG where magic is indeed very subtle and rare; yet still not as rare as in Tolkien. Since much of the way the system was put together was purpose built, it is not really surprising that it feels better than most.