Well balanced units

I'm not sure how this will work as we can design our own units(mundane ones at least), but perhaps if there are premade fantastic units(such as dragons) such things should be taken into account.

I think it will be handled with what you lteach to your men. you can create scouts by just giving them a club and teaching them how to move fast and stealthy. Thaht wouldn't cost you much. But you could also create an uber scout with great armor, magical weapons, uber fast move, night vision and so on. But it would take loooong before completion

So the game won't balance it for you. YOU will have to balance what units you create

Given that youc reate units in game, the game will have to balance it somehow.  Otherwise, everyone will be unleashing hordes of the uber-swordsmen-of-doom-riding-dragons (TM)!

That said, I imagine resource availability will be a very effective balancing agent.

Exactly. You'll have some ressources and YOu have to balance your army. And I think an USODRD (uber swordsmen of doom riding dragon TM) won't be in huge numbers cause you'll need lots of things to create such a unit. So it balance itself. No, when I say you will have to balance your army, I think that you'll have to create the units you need. And if you don't create usefull unit then you'll probably lose

Of course, if the map has 3454326546524654 ressources of adamantine, ridable dragons, adamantine for your swords and armors then ... well .. you see what I mean.

I don't think we're talking the same balance here.  I'm talking about gameplay balance in the sense that having two options, one which costs X and gains Y, while the other costs 1/2X and gains 2Y is 'unbalanced'.

I think the trick is to build different factions, and different strategies, so that the same approach doesn't work best for every faction.  Heroes of Might & Magicwas a great gameplay system, but you were almost NEVER rewarded for focusing on creating lots of small units before moving on to the larger units.

Dominions did a much better job of balancing this across different factions, but they used very tightly scripted units with very specific abilities.

I hope the Elemental designers give us different paths to success, even for military approaches, as opposed to relying on the "uberstack" or "uberunit" methodology that underlies end-game strategy for most 4x games. 

On the other hand, I also hope they make us evaluate trade-offs in our units, so any force I have will have certain weaknesses, and every decision to feature certain units means I sacrifice another path.  Most games give you the option of getting archers first, or getting Iron weapons first, but the trade-offs involved in those choices aren't very big, and I can usually get both without much sacrifice.  I definitely enjoy 4x games where I have to manage around certain weaknesses in my army, even in the late mid-game and beyond.

My hope is that players will have to balance themselves. Every one of your actions will have a consequence. Plate armour is extremely expensive compared to all other options, its very heavy, rusts, requires constant repairs, and last but not least it must be fitted perfectly to the user. Arming your units with plate armour will then be an extreme feat of logistics.

Want dragon mounts? I hope you can feed them. A dragon busy fighting for you doesn't have time to hunt and your wars may take it to lands where there isn't sufficient game.