Show some respect. He's the gratest warrior from our town.

The rest of the outfit not so much

Looks like they're basically moccasins. Comfy in the right context but basically no support. They would need replaced frequently too...often enough that I wouldn't be surprised if common people did repairs themselves.

I would think you'd focus on simple impact. Armor doesn't fully protect against that, so if you hit hard enough with a sword, it's still going to hurt like hell, maybe cause serious injury.

Like how bullet-resistant vests work. Depending on the tech in the vest (and the round), you're still getting injured - perhaps enough to keep you out of the fight.

A good example is modern helmets (both motorcycle and bicycle). I got a concussion while wearing each of them. They kept me from having a more serious brain injury or even death. And my helmets work far better than what this guy is wearing.

This soldier getting hit in the head is still going to feel it, maybe even knock him out or kill him.

A big part of Roman gladiator games was the show and the contrast - most likely, a Crupellarius, as a heavy gladiator, would have been paired against an unarmored Retiarius, with a trident and a net. The tactic of a Retiarius against other heavy gladiators was to evade and exhaust them before binding/tangling them and 'finishing' them, whether by bringing them to a surrender or wounding them. One imagines a similar tactic would be employed against this heavy bastard.

But even if no serious wounds are inflicted, the fight is what matters - you have to give the crowd a show, and everything else is secondary!