I flat out disagree with your logic for multiple reasons.
But to put it plainly in a very simple and direct understanding, if you claim Oracle should be shared with Shadow because of “Void-like” reasoning… what because of the multiple potential futures? While I don’t think that is really a concrete foundation to build off… besides the point really, what you have to at least acknowledge is that we already have “Voidweaver” as a spec that anything "Void-like- would fall under.
Shadow is more than just “Void” and “Old God” themes. Those themes can easily fit with Archon as if it was Voidweaver and Oracle… then BOTH are “Void” related? That is nonsense.
With Archon, you have a simple explanation that works for both Holy and Shadow. Both Holy and Shadow being the “Masters” of such power and at the “pinnacle” point of power in their respective cosmic leanings.
We can explore some descriptions of such titles in history…
Archon (Greek: ἄρχων, romanized: árchōn, plural: ἄρχοντες, árchontes ) is a Greek word that means “ruler”, frequently used as the title of a specific public office. It is the masculine present participle of the verb stem αρχ-, meaning “to be first, to rule”, derived from the same root as words such as monarch and hierarchy.
In essence, a ruler. So if Holy is an Archon, how are they ruling? They are ruling by becoming light itself where as Paladins wield the light, Priests manifest themselves as light.
- Apotheosis
[Miracle Worker: Gain a charge / Reset the cooldown] of your Holy Words, and enter a pure Holy form for 20 sec, increasing the cooldown reductions to your Holy Words by 300% and reducing their cost by 100%.
Apotheosis
noun
- the highest point in the development of something; culmination or climax.
Similar:
culmination. climax, crowning, moment, peak, pinnacle, summit, zenith, apex, acme, apogee, high point, highest point, height, high water mark
- the elevation of someone to divine status; deification.
So what is the Shadow equivalent? Well compared to Apotheosis, Shadowform is basically the visual opposite. One you are engulfed in Holy Magic while the other you are engulfed in Shadow Magic.
In a sense, Shadow is the reflection / shadow of Holy in that cosmic counterbalance sort of way.
You can see such examples in game with the Naaru and Dark Naaru. Since we have Holy having aspects of Naaru, we can easily see Shadow having aspects of Dark Naaru.
Dark naarueditedit source
Naaru can die, but if their physical form is damaged, it may bleed their energy causing them to enter a darkened state[55] in which they are weakened and produce void energies,[56] becoming dark naaru [57][15] (Dark Naaru)[58] or darkened naaru.[59] A naaru’s darkened state is different than death. Their energy may take up to one thousand years to regenerate.[60] It should be noted that some darkened naaru still appear to harbor altruistic intentions; however, their weakened state may be exploited for nefarious purposes, such as creating void minions[61] and raising the undead.[62] It is unknown if this cycle occurs naturally without an external catalyst. Examples of darkened naaru are D’ore, M’uru, K’ure, and K’ara. Thrice, darkened naaru have also been shown to transform further into void gods; though in all known occasions this was only when their light was forcibly drained by an outside party, so it does not seem to be a natural phenomenon and is normally extremely rare. The ethereal Locus-Walker noted that the few cases of naaru falling into Void he knew of had occurred when mortals were involved, which he thought carried fascinating implications.[63]
To conclude:
Anything “Void” related should find itself in Voidweaver and since Voidweaver is not up for debate for Shadow having access to it, it makes no sense to have 2 different Void related Hero Talent Trees connected to shadow as that defeats the purpose sharing a similar bridge/effect with the other counter specs.
Makes no sense for the direction of “Oracle” to be void related when Voidweaver is also Void related. That means Oracle really is not really aligning itself with predictions of the future in the way your thinking with the many future possibilities that Void has.
What Oracle really is / should be is something like this… (using your Delphi example)
https://www.thecollector.com/oracle-of-delphi/
What exactly is an oracle? Or, more specifically, what was an oracle in an ancient Greek context? The communication of divine knowledge from god to mortal, also known as divination, played a major role in ancient Greek religion. Divination took many forms, from the study of sacrificial entrails to the interpretation of the flight of birds. But perhaps the most important form of divination was the practice of consultation of a god through an intermediary. This intermediary was known as an oracle.
That is not really mentioning “future possibilities” like the Void is that your trying to connect.