I'll suggest ancient stuff:
If you want an ancient unit, then there are options such as the Scythed Chariot (regular chariot with collateral damage on 1 unit and perhaps just +50% vs melee rather than the axe bonus), Hypaspistai for an axe/sword/spear modification with a bonus when defending to represent high morale and the "shield-bearer" idea of the actual unit. For a more novel idea, an archer replacement with slinger - strength remains the same but it has 2 first strikes, a 10% chance to withdraw from combat, Flanking 1 and reduced building cost by 5 hammers. Interesting for a really alternate attacking unit.
If the civilization were the Hittites which I could well picture as atleast Industrial (not really Philosophical though), a Foundry or Armory to replace Forge would work well their theme. I don't think the bonus should be to have the health penalty removed but instead have melee/gunpowder units built in that city to have combat 1 out of the gate - sort of like having aggressive at the cost of a forge. Alternatively, it could just feature +0,5 hammers per resource involved in some sort of forging (Iron, Copper, Gold, Silver, Aluminum, Coal). Bonus wouldn't be cumulative for multiple sources of resource but just 1 hammer per access to said resources. The Hittite UU would obviously be the scythed chariot or alternatively a beefed up swordsman (which is admittedly rather moot with Praetorians already in game).
Those are all I could come up with for now.