If I were the devil I'd distract the youth leaders with more and more meetings. I'd get them so involved with well-intentioned youth ministry "stuff" that they didn't have time to actually make and multiply young disciples.
If I were the devil I'd get youth leaders to minimize the importance of intercessory prayer in their own lives and their youth ministry meetings. I'd have them focus all of their time on programming and preparation, leaving hardly any time for prayer. I'd so crowd their schedules and programs with good things that they miss the best things from God wrought through prayer.
If I were the devil I'd attack youth leaders with porn. I'd get them so steeped in this easy-to-acess sin that they couldn't rid themselves of the hard-to-shake-shame that accompanies it. I'd make them feel that they didn't need confess their porn struggles to anyone and that they could break this habit on their own. I'd seek to so isolate them in their sin that it became a never-ending loop of lust and shame. I'd make them feel that breaking the cycle was absolutely hopeless. I'd do this until something broke and, they were either caught and fired, or they actually crossed a line with someone they were lusting after.
If I were the devil I'd get youth leaders to embrace a typical youth ministry model that keeps it light, makes it fun and holds off on getting serious about evangelism until teenagers were spiritually ready. I'd keep them steeped in a safe and traditional approach to youth ministry and do everything in my power to keep them far away from a Gospel advancing approach.
If I were the devil I'd get youth leaders to do lots of good things with their youth groups. I'd get them to build houses for the needy, give food to the poor and reach out to the hurting. I'd encourage them to do all of these things in the name of Jesus but without ever actually sharing the message of the Gospel to those they were serving. I'd convince these youth leaders that preaching the gospel was action and service alone and that the message of Jesus must merely be lived with our lives and not shared with our lips.
If I were the devil I'd seek to discourage the single youth leaders and distract the married ones. I'd wake them in the morning with envy and tuck them in bed at night with discontentment. I'd seek to turn every sin into an addiction, every good thing into an idol, every frustration into a bitterness, every problem into a worry and every interaction with that co-worker (or student) into a temptation.
These are the things that I would do if I were the devil to destroy youth leaders. But I'm not the devil. Satan is. And he is very good at being very bad.
If you were the devil how would you attack youth leaders?