For a mere two mana, you can bring a non-legendary creature from the graveyard back to the battlefield with a -1/-1 counter on it
Its almost impossible to play the kind of control deck that operates entirely at instant speed and controls the game long-term, almost every deck needs to be proactive, and that tends to mean a lot of tapping mana on your own turn
With Battle Cry Goblin, they essentially become their own (exceptionally good) archetype
The most notable change to how we rate Commander decks is the Game Changers list a selection of cards that often have a huge impact on the winners and losers, as identified by the Commander Format Panel
(White, Green, Red can easily destroy an artifact, Blue -- counters, bounces or steals, Black can either discard it first or use rare stuff like Gate to Phyrexia)
Esika, God of the Tree / The Prismatic Bridge Esika, God of the Tree is the perfect example of a powerful commander that also works well in group hug