Healing
wands, my friends, or something rechargeable. Amulet that gives an aura of health regen, etc. If you're spreading healing apparatus among your troops, probably better to go for dedicated healers among the soldiers, equipped with methods to heal many over a period of time instead of just one, once. Healing potions for everyone would be horribly inefficient when you could train 1/10 or 1/20th of your army as dedicated medics and give them the tools to do their job well.
... which leads to the question of item enchantment and creation. Any words on this? Will we be able to make battle standards that offer regeneration and flaming weapons to nearby troops? Will kamikaze (explode-on-death) items be makable? Will we be able to combine that with a slave collar to send our enslaved foes screaming toward their former allies as living artillery (possibly catapult delivered)? Slap a band of regeneration on a captured dragon and repeatedly skin it for armor material? Teleporting arrows? Teleporting kamikaze slave goblins?
The list could go on, and on, and on, but being that it's an army-leading game, the existence (or lack thereof) of force multipliers would be particularly interesting. I want that battle standard. I want everfilling pots of troll blood to dip my terribly injured warriors in. I want dragon heads on sticks, breathing unending gouts of flame on my foes. I want enemy-targeting kill-switch enchantments on my commanders, to spew arcs of lightning on their murderers, and then consume the commander's corpse and resurrect it as a lightning elemental to further wreck havoc upon my opponents. Stuff like that
+1 keen is fine for solo buggers and small parties, but epic armies need epic kit!