Since they revealed most of the Mystical Archive bonus sheet, it's a good time for a reality check of how often all those chase mythics will show up.
7/8 packs will have an Uncommon SOA card In that 1/8th pack you have slightly less than 1/4 of a chance of a mythic and the rest are rare
Compare this to the original Strixhaven Draft Boosters:
Where Mythics were over twice as common and Rares almost 3 times as common
So the pull rates of the best cards have been heavily nerfed
Sourced from the bottom of the collecting article for SOS and the one for original Strixhaven
Honestly I don't remember that well how they were received back then, even though I drafted/watched draft streams quite a bit during Strixhaven.
But it's always a very fine line imo. Sometimes having these extra cards can be good for variety and make you draft interesting deck archetypes the format usually wouldn't support. But the more powerful cards the higher the risk the format is defined by bombs.
Strixhaven did have the advantage that the extra cards were instants/sorceries which both meshed well with the theme and a lot of the cards were just efficient removal, which is much better for draft than big bomby creatures or enchantments.
I also think it's reasonable to assume the decision for lower drop rates had very little to do with concerns about draft.