Thing is she is not really an arcanist/mage as they define it. She doesn't bend reality to her will. She produces repeatable, consistent results that can be taught to anyone. No need for any waking up. Arcane magic can be taught to any person of above average intelligence or just capable of memorizing the mental constructs needed for its use. Ultimately arcane magic is applied science of Planar mechanics that is much more "hard" than Technocracy's own brand.Even if the Technocratic Union did exist in-setting, they'd still have a problem -- a huge one -- with a paradox-free arcanist. Such a person would be a walking embodiment of the notion that the Union's Reality was /false/, and such a Reality Deviant would need to be eradicated at all costs if discovered. We're talking orbital bombardment by fusion warheads here.
Yeah, some probably would want to kill Merildwen but I can easily see it creating a big split in Technocracy where at least some factions want to learn the new much more robust power system that doesn't tend to implode its practitioners on a whim.