I will say i personally really dislike the "Viktor was the mage all along" part -- for the same reason I hate the "Vander and Silco knew ViJinx and their parents all along":
It makes the world feel so... small. And it complicates things that previously weren't complicated at all.
Does this mean Vi and Jinx also knew Silco? Did they recognise him in s1? Or did Silco not ever show up in their childhood - despite being basically one of their two godfathers? Would Vander not have saved ViJinx from the bridge had he not known their mother?
Did Viktor already know Jayce in s1? Was the Viktor who showed Jayce the crystal when young the same Viktor as the one who he met? How come that mage Viktor had more actual mage-like arcane talents, while the mage Viktor we saw later... didnt? How many timelines were there? What does it mean that Jayce was the only one who could show him? Where there other universes where Viktor saved another boy who didnt end up saving the world?
Its also just the "predestined to meet" trope, which I always feel like is a lazy way to make characters important for one another. What 'fate'? What about carving our bond out of this universe, nails and hands dirty and blooded, crafting our own story? Why must it be 'meant to be', can we not simply will it to be so - to make it so it is?
I made a post about how it can be worked around, for example for people who wanna write Canon complacent fanfic without using... this part of the story. I explain why Viktor is Not the mage and different ways the dialogue can be interpreted:
https://www.tumblr.com/belladoes/767989775291531264/explaining-viktors-only-you-can-show-me-this?source=share
