(Kind of scary when you realize there's been thirty-two of them and that's just the tournament-legal ones!) The feature article this week from Skaff Elias talks about Ice Age's design, so I decided to approach the topic from a different vantage point
You can immerse someone by the environment, and the types of decisions they have to make
To determine Sunderflock's total cost, start with the mana cost (or an alternative cost if another card's effect allows you to pay one instead), add any cost increases, then apply any cost reductions
Previously, if you wanted to play something like Jace, the Mind Sculptor, your options were: Jam Jace on turn 4 and hope it survives the turn so you can untap and protect it, or Wait until you have enough mana to play Jace and protect it in the same turn
I also included some cards like Vito, Thorn of the Dusk Rose that help improve Eriettes second ability