So there have been plenty of parallels between the six human Gods and the six Elder Dragons in the past, but with the latest episode concretely establishing that Elder Dragons have a “magic core” (to loosely describe it) which can be taken in order to usurp their position, those parallels are getting firmer.
So why is this relevant now in particular? For a long time now, the plan has been to have Aurene replace one (or perhaps even many) Elder Dragons, so what makes it so "concrete" now. The key is the implication left by Kralkatorik at the end of the latest episode. That he had a parent whose position as Elder Dragon he took, and that this could be the case for the other Elder Dragons as well. Prior to this we thought that the idea of replacing an Elder Dragon was novel, and assumed that the current roster of EDs was the original. But it turns out the EDs themselves aren’t primordial forces created at the birth of the world and intrinsically tied to its balance; rather they are beings born later who simply hold such a power. It's a position that can change hands, much more like the Gods then we may have previously thought.
To list out the similarities:
-They hold magic at a level that can threaten the world
-This magic has some form of "core" that can be transferred between like-individuals
-The individual has a great capacity for absorbing magic
-This "magic core" has a particular domain
I'll flesh out these points of similarity more below, but the long and the short of it is that I think the Gods must have been an equivalent existence on their home world as Elder Dragons are on Tyria. Not necessarily identical, but operating under a similar system in a similar capacity. There’s been back and forth discussion about just how similar or dissimilar the Gods and Elder Dragons are since Guild Wars 2 released, but with the information we have now I think they are in fact the same kind of existence. The gods are holders of magic domains which use to maintain the balance of a now dead world.
The Gods abandoned their home world, so I think it’s fair to speculate something catastrophic may have happened. We’ve gotten lore snippets in games that establish that they viewed Tyria as a "garden", and with their plans here failing due to the presence of the Elder Dragons, they are now in search of a new "garden". I think their intention is to recreate their home world, having taken their now abandoned world’s magic to plant it in a new seed world where they can carefully manage and nurture it.
So back to the similarities.
Going in order, the death of a God has been repeatedly told to be a world ending event if not contained, and it’s firmly established in the story at this point that too many Elder Dragons dying will lead to the destruction of the world. I think it’s sensible that more Elder Dragons need to die then gods for world ending consequences to occur. This isn’t because one is more or less powerful then the other, but instead because of their relationship to Tyria. Tyria’s system (The All) is still intact and functional, it has some fault tolerance so to speak, and so can deal with a couple ED deaths. The gods on the other hand represent foreign power, so unleashing their surplus of magic isn’t something Tyria can handle even one of. The Elder Dragon’s magic disperses into the world because they are of this world. The Gods are not, and so it explodes out destructively.
The concept of a “magic core” that can change holders is, as mentioned before, well established for the Gods. It happened with Grenth, Kormir, Balthazar x2, and has been implied to happen further back in the Gods’ history. On the Elder Dragon side, we’ve wanted to do this for a while with Aurene, dead ED magic is taken by other EDs, and now with the latest episode it has actually happened with Aurene, and we have indications that such a transfer has happened at least one other time in the past with Kralk. There’s also the “like-individuals” bit. With godhood, we always see it change hands between humans. While with the Elder Dragons, it has been between dragons. So it seems Tyria’s magic may have some sort of compatibility with dragons as containers, while that of the God’s is with humans. Balthazar ultimately failed to take Kralkatorik’s power. This was due to our interference, but it would be interesting to know if he would have even been able to properly take and handle all of Kralk’s power to begin with. Balth was a touch mad at this point, and the other Gods certainly didn’t see this as an option. Perhaps that’s the reason why.
The individual having a great capacity to absorb magic is something well known for the Elder Dragons. The Elder Dragons are all about absorbing magic, and we see this happen with Aurene throughout her story too. On the Gods’ side of things, we see Balthazar absorb the blood stone explosion as well as some Elder Dragon magic from Primordus/Jormag/Kralkatorik, and he was capable of this as an individual even after losing his godhood. To some degree we see this with Kormir as well. As a human she doesn’t seem to have this capacity normally, but the Gods give her their blessing which enabled her to then be able to take in Abaddon’s power. The blessing here may have had a component that increases her capacity for magic absorption. I think the Gods are actually just as capable of absorbing magic as Elder Dragons. That they don’t on Tyria is because of compatibility issues (i.e. not absorbing another domain's magic). Even for Elder Dragons, absorbing too much magic from another domain torments them to the point of madness. As shown with Kralkatorik, it pushes them into a crazed state of magic seeking. Balthazar and Abaddon could also be viewed as having been “driven mad” by something. Perhaps this is a part of our answer. Also note that Kralkatorik was tormented by Balthazar’s magic just as he was with Mordremoth and Zhaitan’s. God or ED, the magic was having the same effect.
Finally we have this idea of domains. I think what’s more important here is the fact that each group is split into domains, and less that these domains directly line up with one another between the two groups. In the end they are of different worlds so I don’t think the domains particularly have to be the same, given that the worlds themselves wouldn’t be the same. We do see a fair bit of overlap though, and in both cases the domains can represent either primordial forces (elements) or concepts. In both cases they tend to have multiple domains, with one as a primary. The domains can also be somewhat flexible in how they present; the domain of Knowledge can be styled as both Secrets (Abaddon) and Truth (Kormir) for example.
TL;DR the 6 human Gods are the “Elder Dragons” of another world. An old idea with some new supporting facts and perspectives.
Or here's a fun alternative. Humans killed the Elder Dragons of their home world, thus dooming it. So six of them absorbed the magic and fled with what ever human survivors they could.