Saffgor: Yeah this is obviously very good in Commander, but probably still worse than one of the main Sword of X&Y cards
While Jokulmorder's mana value is great compared to its size, the true cost of this creature comes alongside the fact that you have to sacrifice five lands once it enters the battlefield
P/T Number 100 Language English Legal Formats Commander, Legacy, Modern, Pauper, Vintage Not Legal Formats Alchemy, Brawl, Competitive Brawl, Historic, Pioneer, Standard, Timeless Rulings (9/25/2006) If the triggered ability doesn't resolve (the targeted land becomes an illegal target, for example), Cyclopean Giant remains in the graveyard
Its happened before
There are also some money cards in the set that you cant help but grin when you open
destroys a bunch of creatures of equal toughness, which can be very punishing against another token deck