Armor only one side.

Hope your enemy isn't smart enough to simply aim attacks at the other side.

What doesn't make sense is the thighplates on the other side. It might make sense to armor only one side if you're going to be using a regimented line-fighting style. You only present the armored side, and the existence of the rest of the line prevents the enemy from choosing to strike anywhere else. (The use of a polearm weapon makes this even more plausible.) However, the off-side thighplates makes no sense in that scheme.

This is obviously 'gladiator gear'. Chosen for style more than practicality and meant for fighting before spectators.

You could also wager that, given the protective boots, and the arm/should plating, as well as the thick metals which are made of iron and not bronze, and the lack of a gladiatorial helmet, and the large weapon. That this guys a "Berserker" or some other form of it.

Not every gladiator style in fiction has to be the Roman style exactly. The armor still looks more stylish than practical.

As for the 'large weapon', polearms like that are excellent at making enemies regret charges. Not so excellent for charging into the fray yourself. I wouldn't call it a defensive weapon so much as say that it takes discipline to use properly.

Of course, the artist has the last word. What's the source on this? I think the picture is really cool.

I think he's going to rugby tackle his way through...

I love dragoons they're great as a fighter class. Lack of magic but specialize in jump attacks. They always don light armor