Choosing an empire in Anvil Empires
Choose the empire your friends or House will play with, then consider its visual identity. Pagans, Ancients and Remnants have distinct clothing designs. The new default deployment clothes described in the September update have no gameplay benefit; that does not mean all equipment shares the same properties.
Clothing and equipment are separate choices
The Ancients' default outfits use wool and leather, Pagan outfits use linen with embroidered fabric, and Remnant outfits use layered linen wraps. For a fighting loadout, compare the weapon, armour and clothing you actually equip rather than treating a visual theme as a damage bonus.
Do default deployment clothes improve combat stats?
The September clothing announcement describes the default outfits as cosmetic. Equipped clothing, armour and weapons remain separate choices with their own properties.