Useless or redundant units?

[B0rsuk]

Let's assume the 2 units are 10 gold 20 resource each.
And the 20horde is 10 gold 2 resource each.

20horde is 200 gold 40 res.
2 units are 20 gold 40 res.

20horde consumes 10x as much supplies.
20horde costs 30 upkeep per turn.
2 heavies cost 3 gold per turn.
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There should be a global enchantment that makes each unit cos -1 upkeep (gold). It would make quite a difference for hordes.

[Teraswaerto]

All that is true, but sometimes it wont make any difference. If a decisive battle is imminent, for example, you'll not care about upkeep or supplies.

[B0rsuk]

If decisive battle is imminent, I guess it's the best idea to use Pythium gladiators.
Ironically, in long run it may be easier to amass heavy armor units, which is kinda strange.
With heavies, you tend to have more gold left. For this gold, you can build extra forts, for example. So you can recruit even more heavies.
How about history ? Were heavily armored soldiers paid more ? Probably not. First of all, as far as I know, early medieval armored soldiers were simply nobles, because no one else could afford a sword, armor, horse....

[Manuk]

Useless is not to be a light unit. useless is to be another better unit so it make the first unit redundant.
It´s always better to recruit tribal shortbows intead of generic ones because they cost 8g intead of 10g and cost less resources, and have map movement 2 instead of 1, and they have a bonus dependant on the tribe (deer tribe have better defense).
other tribesmen are ok if you have a sudden war and are in need of some bulk force. low resource and special ability like if you mass the guys with two daggers cover the battle front filling the gaps between your heavy elites and delivering 2 attacks to lessen the defense thanks to multiple attacks effect.
bear tribe javeliners have extra strenght and this means more range of throw and more damage to hand to hand.
on the other hand light cavarly archers are a little crappy.
but normal light cavalry can buy you quick flankers.
I often overlook recruiting barbarians because of they high cost and little survability. so of indt units i find them to be near the worst units.

[Teraswaerto]

Barbarians can deal some mean damage with their strenght and heavy 2-weapons, useful if you need to punch through armor or take down units with lots of hitpoints.

It's true that some units like light cavalry archers, without lances or something like that, really seem rather useless. The higher map move is the only benefit I can think of for them.