So at this point, I'm thinking the biggest reason why Vanguard is no longer a supported format is simply that it's completely devoid of balance. I am one of the noticeable segment of players who plays to enjoy the game, rather than to win at any cost, but since Wizards seems to believe (whether or not accurately) that their playerbase consists mostly of Spikes who want a competitive environment, Vanguard is basically unsalvageable; there is simply no way that Wizards can avoid enabling utterly broken decks in Vanguard, leading competitive players to think that the format is completely random and pointless. (The most current example of this would be the way that Turntimber Ranger in a Seshiro deck set to Allies is a near-instant win - this can happen on turn 3 with enough mana elves, and the only real defenses are Wrath and Stronghold Discipline.)
So I put it to the community: is Vanguard really impossible to "unbreak"? Is there any round of bannings, rules adjustments, and the like that can possibly restore balance, or will some avatar-deck combinations always be near-guaranteed wins which offer no possibility of a fair fight?
As far as the benefit of the rest of Magic is concerned, gold cards in Legends were executed perfectly. They got all the excitement a designer could hope out of a splashy new mechanic without using up any of the valuable design space. Truly amazing. --Aaron Forsythe's Random Card Comment on Kei Takahashi