High initiative is what makes GC so powerful.
In the battles I've fight with 2 LW/non-GC characters, when one character gets CC'd (especially at the beginning of a fight), I start to get a little nervous. When the second character gets CC'd, chances are a reload is imminent. So the solution for GC or LW/GC is to increase the probability of that happening.
So, (putting the lore of LW and GC aside for a moment) make GC ignore/not benefit from the +5 initiative from Leadership. This should put a GC character behind a lot of enemy creatures in the turn order, and would increase the impact of the vitality drawback. Combined with LW, this would increase the chance that 1 or more PCs are CC'd, thus increasing the chances of the entire party being CC'd, which usually ends badly.
Hell, why not just remove +5 Initiative from Leadership altogether? I bet that would increase difficulty all around.
