Jund Sacrifice is one of those combo-style decks that demand high levels of familiarity from the pilot
So what tends to happen is that eager beavers will trade for a couple of pieces from some exciting new deck (generally right after they see it perform well on stream and the prices are at their highest) only to give up once they realize, holy mackerel, Vengevine is itself a $50 card and Leyline of the Void is up to $60 and you need a playset of Arid Mesa and wait, how much is Blackcleave Cliffs these days
The best card in Foundations Jumpstart has to go to Dionus, Elvish Archdruid (though Rev, Tithe Extractor and Scythecat Cub are strong contenders)
From initial testing, though, this is a faster but worse version of Yawgmoth Combo in Modernwhile you potentially shave a turn off of the combo with a perfect hand, Yawgmoth can play a card advantage game even if the infinite combo is disrupted
Note: There are other Pokmon card types out there
A mechanic that tells you to play a lot of monochrome permanents, while intrinsically interesting, is not extrinsically compelling in a format as high-powered as Legacy