I was looking through the new cards

this pact results in cards being shuffled into the mythos deck.

easy enough but we spent all that time at the beginning setting the mythos cards into the 3 acts.

it seems like sometimes this could be good and sometimes this can be bad depending on how it redistributes the cards.

has anyone had this come up i their games?

Yes I did. Was bad story acually… I lost this game couse mythos deck empty .. .

The key for a good strategy in EH is to understand how the Mythos deck works. You know in each stage of the deck you have X Rumors, Y Reckonings and Z Surges, and you often metagame on that, knowing when it's more likely for conditions to be tested and so on. The Pact with Eibon actually destroys this type of metagaming. It's a nice card, imho, but it can have disatreous consequences