I often see talk of Unit such-and-such, Attack(x), Def(y) and so forth but I can't see any data relating to 'weapon reach' for the various unit types. Or I may be looking in the wrong place.

Would I be right in guessing that this factor isn't modelled in the game?

The nearest we get to it is things like spears getting a defence bonus against cavalry, which reflects their ability to hold horses at a distance and out of reach of a sword but, in practice, they still take losses anyway.

I hear much talk of 'swords beat spears every time' but, thinking about it, if spears can hold horsemen at bay, what chances does an attacking swordsman have? Surely they're going to get a speartip thrust through their chest before they can get within sword-striking distance?

I'm not arguing that the spears can actually kill all the swords in a straight fight though. The swordsmen can easily stand back and dodge side to side to avoid the odd thrust, or parry with a shield. In short, it should be a stalemate situation until something else comes in to flank the spears.

This, of course is the whole point of the 'shield wall'. If the line can be made long enough, it's unflankable. Or at least the detour to a flank which is a great distance away will divide an attackers force in the centre, risking local outnumbering should the defenders use this opportunity to charge en masse.

Then there's the pike and musket era, when 'push of pikes' was a central part of ECW battles. Basically a prolonged scrum where you attempt to gain ground by sheer muscle power but would it be correct to say that relatively few casualties resulted from pike stab injuries and it was the musketry which did most of the killing?

Btw, I've seen enough TV programmes featuring Mike Loades' words of wisdom to know that reach isn't everything. The Greek/Roman short sword could be concealed behind the shield until the last split second, so the defender doesn't know whether to parry high/low, left/right and, if they should strike first, the attacker parries with shield, closes in and gets a free strike. A stabbing action rather than slash.