So the long and short of it is Odin, through guilt, decided a section of the multiverse for Earth is worth a chance for one single person to have a better life?
If you disregard all the people who had to suffer and/or die in the process of Taylor's journey to defeat Scion, up to and including the people who were directly killed while under Khepri's control? Then yes, Odin is an irresponsible bag of dicks placing one girl's happiness over the safety of a big chunk of alternate Earths.
While it sounds good the way you said it what it boils down to is what I just wrote.
Alright? Though in that same vein, 'Macbeth' sounded good the way Shakespeare wrote it, but that doesn't stop me from disparaging it by saying it boils down to, "Guy gets a nice promotion and his scheming bitch of a wife uses it to make him a worse person."
That is a monumental foolish and asshole move, granted it isn't so for Taylor but the risk it would involve...
Or he could have saw what would happen after he did that snip of fate and literally saw it works out so went ahead with his plan *shrugs*.
Could be, sure. I mean, I think it would be a bit weird if we heard from the start of a story that our protagonist was fate-ordained to achieve a Good End, so I don't think that would be a good scene. But if it sets your mind at ease, I'm 100% sure that if Odin thought it necessary, he could just go after Scion himself if he saw that this slice of alt-Earths was suddenly worse off for his decision to give Taylor a kind of power that won't destroy her.
Look, when Odin examined the Loom of Fate, he didn't just see 'Random mortal + power = dead
Sníkjur'. He saw, with the kind of certainty that seems nigh-impossible to mortal minds, that it was
Taylor Hebert that killed the parasite, and it was her parasite-granted power that merely gave her the ability to operate above the level of a 'normal' mortal. It was her will and her resolve that killed the parasite, not her specific power. Queen Administrator just happened to be the specific power that required Taylor to destroy herself for the sake of victory.
The power that Odin gave her is not like that. He sent that hammer down to the girl who would save her world and countless others, and it literally
would not work if she became someone less than that. Could she do it differently, and less painfully? Yes! And that was the point of trading QA for Mjolnir in the first place.
Or, if we're boiling things down to as few words as possible, Odin saw Taylor's future heroism and sacrifice, and decided to give her power himself rather than let her go down a road dictated by powers that were inherently toxic to their holder.