I wish W/R had a sideboard scouring card like Living Wish, but they dont as far as I know.
Lorehold, the Historian imbues each instant or sorcery card in your hand with Miracle 2, enabling powerful surprise plays for a reduced cost
Six of the top ten most played creatures in Commander on EDHREC are manamana dorksdorks for good reason, and Elves decks can take advantage of these cards better than anyone else
You wind up with one set that can do things the others can't, forcing players to counter that set with other cards from it, and generally limiting the creativity with which one can effectively play the game
Early stats suggest that SIRs are in fact found in one in every 100 packs, which is ridiculous , and the golds are in one in every thousand
A lot of people have surmised this, but these examples help to put some flesh on the bones of the idea before prerelease