[William Cloud Hicklin]

Tolkien, interestingly, postulated a world in which weaponry remained essentially stagnent for thousands of years, or even declined. The impression one gets, from the Nirnaeth right through to the Morannon, is that miltech was fixed at about the level of our 12th century or so.

Now, why would this be? Obviously, he wanted to keep gunpowder and firearms out of his world, and that would be conceivably an argument against plate armor (although it's accepted today that 15th-century 'white harness' was actually less cumbersome than mail, in T's day the old notion of helpless ironclad tortoises that needed hoisting into the saddle was still the accepted view). Nonetherless, he could easily have atributed supertech to Dwarves or Noldor, even if just for the First Age- so why not? After all, if his viewpoint is the earlier Middle Ages and its looking back at the Ancients, we know that Roman legionaries (at least for a while) wore the banded lorica segmentata.

Also the missing crossbows- although I suppose they could exist without mention. But I would think the x-bow would be a perfect Orcish weapon. (Not so the Elves, who presumably have ample time for the training required to make a good bowman, or the Rohirrim, since a x-bow ain't a cavalry weapon). But for Orcs- a cheaply made piece of low-tech which requires little trainng, just a degree of brute strength. The AK-47 of the ancient world. And again, why not the Dwarves, esp. since one would assume a Dwarf could stirrup-cock a much heavier xbow than a Man?