To be completely fair, although Nick Bostrom realized the importance of the problem before Eliezer, Eliezer actually did more work on it, and published his work earlier. The earliest publication I can find from Nick on the topic is this short 2003 paper basically just describing the problem, at which time Eliezer had already published Creating Friendly AI 1.0 (which is cited by Nick).
To be completely fair, although Nick Bostrom realized the importance of the problem before Eliezer, Eliezer actually did more work on it, and published his work earlier. The earliest publication I can find from Nick on the topic is this short 2003 paper basically just describing the problem, at which time Eliezer had already published Creating Friendly AI 1.0 (which is cited by Nick).