First, I doubt they'd add in a whole extra pantheon of new gods this late into the game, especially since said pantheon doesn't seem to be known by anyone. Second, the known gods aren't really "good" or "light."
*Lumia may be the goddess of light and healing, but also, you remember how she basically pressured the Boreal Elves into worshipping her or else they wouldn't receive protection, and this led to a whole bunch of them becoming outcast and several others being tortured and starved to death? She doesn't have a squeaky clean history, and has used cruel methods, as shown by that.
*Keros is the god of trickery. He may take care of his people, but he's also practically malicious at times, doing things which are "incredibly cruel" and being feared for what he can do.
*Tira is literally the goddess of death and time. I don't know much about her, but the concept of death and time are, I believe, generally the sort of thing people would associate with a "dark" pantheon, yet she's part of the Seven nonetheless.
*Sorra is the goddess of several nice things, like flight and freedom, but she's also apparently the goddess of storms, and, well, storms generally aren't pleasant. In some more expanded religions, if there's a god of storms, they're oftentimes the evil counterpart to a normal god of water or the sea or rain.
*Mallach is the god of a church which we know basically raises and indoctrinates children into selling out their bodies to raise more money for his church, and while there's nothing wrong with sex, it still feels weird to basically raise people specifically so that they can get fucked.
*Nareva, well, part of her domain is secrets. The "God of Darkness" you gave an example of can't be the patron of secrets, because that's literally already Nareva's job.
The only member of the Seven that I can think of which doesn't have some aspect which conflicts with this is Velun, and even so, he's apparently quick to anger and he's "unimaginably wrathful" when he's angry.
The Seven are very much concerned with their image, but also, they do want to get things done. They just have a lot of their own shit to deal with, and also don't want to baby the mortal races. They don't want to coddle them, hold their hand and do everything, because that, to them, would weaken the mortals, make them worse off, etc. They do things when they truly need to, and when it comes to Kas, they do not feel it's something that necessitates direct involvement. Especially since it seems that, were they to get directly involved, rather than acting through an intermediary, they'd cause very large amounts of collateral damage.
oh that's an argument for me. For example, I missed the mention of Tyra and Nareva in the game.
Again, I usually forget that the "light pantheon" for 90% of people is equivalent to the "good pantheon". I personally do not consider the two concepts to be the same.
Light, in my understanding, is a force that seeks to change everything in accordance with its vision, burning out and exposing the shortcomings of others, if you do not accept his point of view, the light will burn and scorch you, condemning you as a heretic.
Darkness, in my understanding, accepts us as we are, no matter how ugly or vicious we are. Unlike Light, with his fanatical pursuit of excellence, he is calm and patient.
Light cannot exist without sacrifices, it always consumes something for its existence, and darkness exists by itself, it is the opposite of Light.
And therefore, when I talk about the "Light Pantheon", I am talking about the gods, whose faith is most widespread and considered a blessing among followers. The same Lumia is really ambiguous for us as players, but for its followers it is the Good Goddess. Like Mallah and Velun, and others.
By the way, as far as Keros is concerned, I do not think that many inhabitants of the world will agree with the definition of him as the god of light. If I understand correctly, then Kitsune and therefore Keros are not very welcome outside their commune, especially given their ability to drain souls.
So Keros is definitely a "good" God only for his people and followers.
About the "Dark Pantheon" stealing someone's sphere of activity. I just made an offer by throwing ideas at the wall. And what will come of this and whether the authors will be interested in my idea at all is another question.
And let's be honest "The Dark Pantheon" may not even be gods in our usual sense. This could be a reference to the Tribunal from TES 3: Morovind or the star gods of C'tan from Warhammer 40k. Or, in general, you can make them creatures of Darkness and Chaos, Great Old Ones, and even ancient and powerful elementals. The main idea is not to make them unambiguous evil but rather patrons of the outcast by the rest of the world and the dominant pantheon.
As a PC, we see the world from the point of view that NPCs show us, and what a coincidence, most of them are followers of the most famous gods (I would call them "winners" in the race for faith), but they may be little-known ("losers "That patronize those who have been rejected or rejected by the" winners ").
In general, it is quite difficult for me to explain my point of view at my "Retarded" level of English (An honest assessment of yourself, no insults to anyone). Even just writing is pain, the lack of practice and fear misunderstatement affects. I can say im one of the few CoC and TiTS fans in far and snowy Russia (yeah, it's snowy... outside 34+) and try to spread it as "holly grail" among those who can understand. But half of the people drop game on the phrase "only in English", although I must admit that this is one of the few works in which Ctrl + C Ctrl + v in the translator is a working strategy. I played CoC 1 with a translator and much later I could start reading and understanding the original.