Sheldon Menery was a founding member of the Commander Rules Committee, instrumental in its inception and early development
It is also the card type with the least amount of design space, so in my role as head designer, one of the things I've championed has been slowing down the evolution of planeswalkers to make sure we're "squeezing all the toothpaste out of the tube." Because of this, the static ability on Garruk Relentless was a bit contentious
2018-06-08 To have two commanders, both must have the partner ability (featured in the Magic: The GatheringCommander (2016 Edition) set) or corresponding "partner with" abilities as the game begins
Command Tower is the classic example: Its colorless from a deckbuilding standpoint because it doesnt have colored mana symbols printed on it, but it still fixes you perfectly in-game because it only makes colors your commander actually has
Because delve isn't an alternative cost, it can be used in conjunction with alternative costs, such as flashback
One drawback is that your opponents have more combined life than you have cards in your deck, so it's possible to deck yourself out if you hit a combo too early or without a way to throttle it