Choose one: upkeep, untap, draw, main, combat
The biggest challenge I've found is fast aggro
Intuitive Customization : Reprints and card styles should be easy to understand and collect
All That Glitters, Cranial Plating, Salvage Slasher, Nim Devourer, Digsite Engineer, Urzas Saga, Karn, Scion of Urza, Runaway Trashbot, Bronze Guardian, Monumental Corruption, Darksteel Juggernaut, Armix, Filigree Thrasher, Shambling Suit, Battle at the Bridge, Herald of Anguish, Inspiring Statuary, Sly Requisitioner all of these cards scale in a way that favors the Commander environment
It mixes a theme of caring about artifacts with mana value 4 or greater with monarch cards as a subtheme