A sweepers goal is to remove as many of your opponents resources as possible with one card, and no card does it better than Balance
If I knew I would only be playing control mirrors, I would add the dual lands and play Pyroblast, but I firmly believe against an open field, Id rather have the stability of basic lands and two colors to push through the variety of decks every Legacy event presents
Check the Rosette Pattern Rather than use thousands of colors of ink, printers use a handful of colors in combination
For those looking to make Final Fantasy -themed decks, three cards are perfect for it because they can scale all the way to cEDH (competitive Commander)
Offering access to the entire color pie, Wizards is typically very careful when it comes to printing these cards
Aside from the rotation, its also important to take a look at the ban list and restrictions