The thing about the Sundered on the Shards is that they all still have physical bodies. What's more is that they have physical bodies of the same size and shape as people of the Source.
This means on a physical level, they are just as much a being as any Sundered from the Source.
With what we learned from, "In from the Cold" was that a physical body matters a great deal when it comes to expressing power. Hell, we learned that from our battle with Hades. "I AM STIFLED BY THIS VESSEL OF FLESH!" In all the ways that a bigger soul matters, it seems that for the most part, at least via Aether power expression, a big whole soul cannot express 14/14ths power through a Sundered body.
And that's before we go into all the ways technique can matter. Like, hell, for as strong as the WoL is they still succumb to the effects of a roofie in Heavensward. Ultimate Godslayer, Popeslayer, Dragonslayer extraordinaire... laid low by a barmaid. It's little wonder there's a bit of confusion when it comes to power levels and power level expression.
When we went to The First, we went to a post-apocalyptic world where every being had been surviving for a century by whatever means necessary. We fought the physical creme of the crop, those who could take did. Those creatures that were strong lived. Leveling in Shadowbringers pre-stat squish felt to me like a formality. The Ran'jit battle was a poor expression of antagonist power if you played tank when SHB first dropped, particularly if you played DRK. Between The Blackest Night and the other tank cooldowns, it was possible to negate more than half the damage of Ran'jit's down for the count Raiton(his Fire and Thunder moves are rehashes of Ninja's Katon and Raiton, while his Snake's moves are Alte Roite moveset). With the regen from the solo duty buff, this meant you would be down for the count on DRK with full HP, not sweating at all.
Compare that to the Zenos battles where once Zenos flexes his crimson aura, your damage drops to double/triple digits and you miss thanks to level difference 25% of the time...
We then get Ran'jit's backstory, and he's been the head coach of Eulmore's military for like half of the century or however long it's supposed to have been for him to have raised half a gaggle of Minfilias and teach them how to fight. We can conclude that he had a very strong body and mastery level of the techniques he employed. All very impressive, but then we have Thancred able to fight him to a standstill as a Solid Light ghost employing shells charged by Ryne and a technique only available to him due to his ghostly state. This is Thancred fighting with a set of skills he's only had for less than half a decade with only his soul mimicking his physical body, which I suppose is still wearing aetherially enhanced garments.
All in all, everything is a big mess, but for as much of a mess as it is, it's nice to see that a lot of the small things like finesse, armor, drugs, temperature, and all that jazz still matter to some degree in this story about slaying gods and would-be gods and man-made gods. In this way, it's very much like reading Greek or Norse mythology wherein depending on whose account of a God you're reading, stuff like Zeus getting his tendons cut by an Adamant sickle causes him to lose his first bout with Typhon.