And yet again I visit this place earlier than planned...
Regarding that Aquaman costume, I did some detective work (read - have starred at the zoomed-in photo for two days and made some comparisons

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and I am 90% positive that it does not have a scale mail on it, but is in fact a bronze Roman muscle cuirass (which was the idea I considered before, since it works very well with the
Retiarius gladiator aesthetic, so, naturally, I am happy they seemingly went in this direction

) which has the pretty much same pattern Momoa wears on his body in the form of tattoos.
Pic of the muscle cuirass:
Pic of zoomed-in costume:
What looks to me like the exactly same pattern as tattoos on Momoa's body and lines on the armor:
Now, Retiarius gladiators didn't wear such armors, none of the gladiators did, for two reasons - they were for most part bare-chested with minimal armor (why bother when they're gonna die anyway, and distress a perfectly good armor in the process

) and muscle cuirasses were worn only by the generals and emperors (and gods in some of their depictions), not even common soldiers had them... so it is certainly fitting for a king.
Now, I understand some of you would prefer the more classic look with the full scale mail. Problem is though that out of all JL members, Aquaman's costume remains the most nonsensical one in the comics, even after the more "realistic" New 52 look the characters got. Thing is, there was never a full sleeved scale mail like the one Aquaman wears in comics. Unlike chainmail, it would obstruct movability of the arms (which would be quite a bugger in a fight) and it would be even less possible for an armor of that sort to be able to look streamlined and stay close to the body in an aesthetically pleasing way like it does on Arthur in the comic books. Historically, there were some "long sleeved" chain mails, but those did not cover inner arms and were also pretty rare. Point of such armors is to cover the chest while trying to as less as possible get in a way of the wearers flexibility.
So, again, if it's the muscle cuirass they went with as from this pic I assume they did, I like it, as it allows them to go for the comic book-like muscled upper body look all of the male JL characters seem to have (which would be lost if it were a scale-mail cuirass), but in a way that is factually accurate and works well with the Retiarius Roman-inspired aesthetic of Momoa's Aquaman (and, of course, '90s Aquaman). And not just that, but the fact that Momoa's tattoos are actually meant to represent real armor (even down to the Mandarin collar on his neck) also goes perfectly in line with the use of Polynesian tattoos which are indeed meant to provide protection and act as an "armor" to the person wearing them. And the very shape of these muscle cuirasses creates that same arc for the "A" belt New 52 Aquaman has. So it's very clever approach by Wilkinson.
I think triangles and spearheads will emulate the chain mail look in parts though... not sure what's going on in the pecs area, but if the armor remains truly faithful to Momoa's tattoos, there should be triangles there as well as the waist area. And I believe that the new pauldron/manica strap has some triangles on it as well... there is definitely some pattern going on there.
Anyway, I may be completely off the mark here, but this is what the armor looks like to me and what to me also makes contextual sense to be the case, so I thought to share these thoughts.
By the way, I prefer these Aquaman's boots/greaves to the BvS ones. That armor on the right seems to be also Atlantean (as it has shell-like bracers as well), possibly Mera's, given that photo of her is near... Flash's ears remind me of Jay Garrick's and seem to be pronounced due to the aerodynamic shape of the helmet/cowl and I'm 99% sure that the black suit in the picture is underarmor or rather muscle suit for Batman's costume, not unlike Cavill's silver mucle suit.
That much from me... bye.