It's great in control builds, mono-black, it's another option for Aristocrats builds in this list, it's strong in many places
If the ability doesn't resolve (either for having its target become illegal or because a spell or ability counters it), the mode chosen for that instance of the ability still counts as being chosen
Options are great, and Retreat to Hagra provides a ton of upside with each land you play
Upgrade Goals I have some specific goals when upgrading Corrupting Influence : Cut the low-impact poison cards Add haste enablers Add the remaining good poison cards Add more proliferate Spend the rest of the budget on general upgrades While the precon is very good overall, the biggest weakness is that there's a bunch of bad poison cards eating up card slots: Blight Mamba, Ichorclaw Myr, Culling Ritual etc
It gives you something excellent to do with your extra mana, growing at a more efficient pace then Figure of Destiny (if you actually have a deck full of Gods Willings and the like)