It's their big overpowered release of the year. Last year's was commander masters. I'm not sure what it was before that because I wasn't into the scene for a long time prior to that.
I have no idea how wotc calculates what they are going to charge retailers, but it certainly seems like they take card value into account, which is crazy because it hasn't released yet and they have no idea how much people will value the cards. So I guess they're just guessing that they will be highly sought after rares/mythics? I honestly don't know.
Maybe there is an actual scientific calculation that goes into it, using the number of rares in the set and the number of rare slots that can exist in a pack or something like that, with some qualitative value for card power.
But at the end of the day it's just "whatever Hasbro thinks it can get away with charging". The power level is probably just a result of the designers doing their best to give players a reason to pay the amount of money Hasbro wants to charge for each pack.
There's a lot of cards in there that are reprints of stuff so old that even I recognize them, which is around the Alara era lol. Is this like a Greatest Hits thing without all the shit commons nobody used? Because that would explain why the average value would be higher than a brand new set.
Magic is a beautiful game but I really wish they'd slow down the releases by like half. This infinite treadmill is going to fast and I'm really not sure I even want to be on an infinite treadmill to begin with.