Each commander precon has some kind of new mechanic or keyword unique to the set, and in Commander 2011's case that ability was join forces. This mechanic essentially allows multiple players to spend mana to bolster a card's effectiveness and power level
Currently, theres a surprisingly good amount of supply for these worse condition variants too
The legendary land cycle with Channel mechanic looks especially interesting, and many consider it to be the best one in years
One would assume the recently released Mythical Island set would be A1, but that is not the case
Creatures (29) 4 Robber of the Rich 4 Fervent Champion 4 Bonecrusher Giant 4 Rimrock Knight 4 Anax, Hardened in the Forge 4 Akoum Hellhound 2 Goldspan Dragon 1 Dragonkin Berserker 2 Birgi, God of Storytelling Lands (21) Spells (10) Between Birgi, Robber of the Rich, and Showdown of the Skalds, red aggro has some serious card flow capabilities
I already talked about the rules, but another aspect that needed a lot of wrangling was the color pie