Just watched the video, and wow, that was awesome. I don't have anything to add to what the guy who recorded it was talking about specifically from the top of my head, but since one of my superpowers is reading, I'd like to point out something else:

Jeff Grubb actually hinted at the flavour of snow mana in The Eternal Ice before the concept even existed in the game (to which it was introduced by Coldsnap, which in turn brought back Jeff Grubb as an author to let him explore this some more). Here's what the novel has to say about how snow mana feels:

"Despite his [Jodah's] dislike of the cold, he thought of mountains - high and majestic, bearing the snowpack on their peaks as if shrouded crowns. He thought of the mountains and of the power that lay within them. The power came to him slowly, as if the magic itself had been frozen. It coalesced as if thick syrup into a dull reddish ball in the back of his mind, slowly growing brighter and brighter, until finally it shone like the flames that Jodah wished were in the hearth." (pp. 12 f.)

I've always loved Grubb's attention to detail and the thought he put into how the flavour of the game would actually work in-universe. It's what made his Magic stories so immersive and believable (it's also what has been virtually absent from Magic stories in the past decade or so, but let's not go there).

Apropos of nothing, I recommend playing Cover of Winter with Eon Hub and going to town. Or Dead of Winter with Kormus Bell, a board full of Snow-Covered Swamps, and, if you want to be really nasty about it, Lethal Vapors.



Edit: Also, you can't tell me Percy Shelley didn't describe how mana and magic work in MtG in his poem 'Mont Blanc', and it's basically about a Snow-Covered Mountain, so it feels appropriate: https://en.wikisource.org/wiki/The_Comp ... nson,_1914)/Poems_written_in_1816#528

If I can pile my English degree on top of my MtG guru knowledge in the same thread, you'd better believe I'll do so

Syrup uh? A lot of early Magic seems to compara mana to fluids.

This is true. In one of the anthologies, Barrin described mana usage in terms very reminiscent of fluid dynamics. The idea being that the spell itself is the release of the fluid pressure and the mage acting as something like a nozzle to dictate the spell's shape.
That, combined with Jodah's mistaken use of white mana in Gathering Dark has always made me curious the effect of spells using the wrong type of mana. Radha did something similar as well, now that I'm thinking on it.

In general how early magic is described seems oddly more tilted towards (fluid, explicitly connected with the mind via memories and going from the base of the spine, etc)

I think that might be just an artifact of the viewpoints we experienced. Early on, they were a lot more loose with the Wizard identity in all colors, but that did mean it turned to be scholarly pursuits.
Druids featured, but they weren't so inclined towards explanations as much as experiences.