There never was, until the modern days, a uniform appearance of troops in any army, except maybe the Roman legions (the shields did bear distinct markings occasionally made by individuals, so not very uniform after all).

The Middle Ages are especially so, given that each soldier had to provide his own armour and weapons. Thus, some would be unarmoured, others could only afford leather jerkins, etc. In truth, there would be even more differences than it is possible to recreate.

The hoplites were similar (in that they needed to buy their own equipment), but the manner of armour consturction pretty much allowed a more-or-less uniform appearance ... the greatest differences IIRC were the helmets and the shields.