Lightning Bolt won't be good enough as our removal package must be able to remove any kind of creature, so exile effects, sacrifice effects, and boardwipe effects are crucial for always keeping the battlefield clear
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owners control with a -1/-1 counter on it.) Illustrated by Adam Rex Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Legal Modern Legal Brawl Legal Legacy Legal Comp
Plus, if you win the game the turn you played the Pact, you never have to worry about that cost
MH3 brought plenty of support for the archetype with adapt creatures, so this Golgari card got even better
But, like with many others on this list, that still wasnt that amazing back then
You'll need to be rolling in cash if you want to own one, though