There are dozens of ways to draw cards from sacrificing creatures, and most of them are far, far better than paying 6 mana and skipping your draw step
Before the invasion of Phyrexiansthe first invasion of Phyrexianssundered the land
Muldrotha lets you play a land and cast a permanent of each type out of your graveyard, letting you re-use the permanents you want to keep sacrificing
From the safest of all the Storms to the most dangerous of all the lieutenants, Loyal Guardian is a wrecking ball in +1/+1 counters decks, like, I dunno, Ghave, Guru of Spores
Update: Since originally writing this review, I've run some into issues with durability with different batches
Darksteel Reactor Darksteel Reactor wins the game if it has 20 or more charge counters, and youll add one counter each turn