Midrange decks also have more robust manabases, meaning they play more lands and actually want to draw lands
1 Sacrifice this artifact and you lose 5 life
His ability also extends to your other Treefolk, letting them hit hard with their beefy toughness totals, and even your opponents creatures, majorly hurting aggressively-statted creatures like 3/1s
Basically, set value is (close to) a zero-sum game, and for every dollar of value Masterpieces series cards have, rares and mythics lose an equal amount of value to keep the box under the cap
The deck box is also a real box that you can put fully sleeved decks into, unlike some the old Commander boxes
it can be done, but it's more difficult to construct a viable mono-color deck than multi-colored decks