Red decks are already explosive, and you have cards with valiant, prowess, as well as the format-defining Slickshot Show-Off
At least one card per pack will be Mythic Rare from among those sets, 3 cards will be Rare or Mythic Rare from among those sets, and the final 2 cards will be Rare or Mythic Rare from the latest of those sets
Unless a card is clearly underpriced and about to sell, there's no urgency
Everything Explore does, this does plus more and while Explore gets a lot of play in decks with no access to Blue, this is still an incredibly good card and it likely impacts formats other than ours
Initial demand is softer for these cards than it is for most non-reprint sets, where the available supply starts at zero and a whole bunch of Standard players are clamoring for their staples