Despite being very powerful, she was needed
Whether it means the cards ubiquity at high levels of play or its rare appearances at Sizzle tables causing games to be less exciting than theyd intended
Concordant Crossroads is a candidate for the main deck in many Reanimator strategies, and being that its an Enchant World, it also acts as a removal spell against The Abyss should you play it second (the most recently cast/resolved Enchant World kills all others in play)
However, another complaint with that set is that it wasn't very flavorful
Of note, these arent bonus sheets but they are subsets, though they lack their own set code, like BIG and OTP were for Outlaws of Thunder Junction
While the Explorer doesn't let you play lands from the top, it does let you play them from the graveyard, all while milling you for each land played, so as to get more lands into the graveyard