Banned and/or Restricted
The latest Magic: The Gathering bans for modern lead me to believe that Wizards of the Coast would like modern to have more variance. That's a valid design choice. Both Birthing Pod and Dig Through Time provided card selection for very low costs, rewarding skilled players disproportionately. As an avowed Spike, I will always prefer less variance. I actively want to the better player to almost always win. Having said that, if you want more people to get into modern as a format, variance is one of the better ways to keep new players.