You'll still need to wait a few turns to get the most out of Barrowgoyf, but for three mana, it's hard to argue with its efficiency
What could have caused this
Most answer cards are viable targets and that tends to be what you are fishing for in the mid and late game
Since you have two partner commanders, Frodo, Adventurous Hobbit and Sam, Loyal Attendant, there are plenty of opportunities to turn your lifegain into game-winning strategies
Partner is a keyword that allows for a legendary creature to be used alongside another legendary creature, allowing a player to use two commanders rather than one, but both cards must feature the partner keyword
By this point, everyone knows about Grixis Shadow, as the deck has been around for a number of years