Armies of Middle Earth during WotR

[Kuruharan]

"Grown strong again" has to be put in the context of these previous losses.

But on the other hand we have to have a certain level of people present for a kingdom to be considered powerful at all. Erebor had to be one of the largest concentrations of dwarves remaining in Middle-earth, I think we can all agree on that. Based on your numbers, you seem to be proposing that only around 10,000-20,000 dwarves (including females and members of other houses) existed at all in Middle-earth at the end of the Third Age. That is impossible to swallow.

And we still have the problem of three day battles not being fought by armies of such tiny numbers. If the dwarves and Bardings were truly as few as you suggest, the Easterlings could literally have just rushed up and lain down on top of them and smothered them and that wouldn't have taken more than a day (see the demise of Isildur). The duration of the battle is a powerful argument that your numbers must be adjusted upwards, and rather substantially at that.

Gandalf's description that the Enemy has few horsemen is not based on any immediate reports (the besieging army has only begun to cross at Osgiliath).

Beg to differ with you on that. The Gondorians at that point would have had some idea of the type of enemies facing them. And why, at a rather critical juncture, would Gandalf be bothering to relay strategic information about the global composition of Sauron's forces when what mattered right then and there was whether the Witch-king had a bevy of horsemen to hand? And, indeed, the way Gandalf phrases that particular line it sure sounds to me like that want of horsemen was only a temporary situation while the Witch-king got them over the river. Gandalf seems to be saying to my eye that the sortie must be made right then while the enemy still had few horsemen on the west side of Anduin.

Just because the Witch-king had few horsemen on the ground at that very moment (or at least few in comparison to the rest of his forces) doesn't mean Sauron or his allies had few elsewhere in the world. Theoretically, Sauron wouldn't have wanted many horsemen at a battle where the geography all around was largely constrained and the primary battle was going to be a siege...although he certainly seemed to have scads of them around in the Battle of Pelennor.

In sum, I don't believe that line has anything to do with the global composition of Sauron's forces.

In the North, on the other hand, there were much larger distances to cover and (as far as we can tell) the pretty flat kingdom of Dale to overrun before they got to the town of Dale itself. Different geographies call for different types of troops.