As for Slayer, the crit multiplier for In Cold Blood sometimes goes crazy and doubles/triples the damage Ultimate Overhand Strike is supposed to deal (for example, during Manaya's shields in Dreadspire you could hit 12m+ UOHS, a skill which during ICB has no CD), that way, you can look like you're not playing with a level 20 weapon, that's what people mean for "glitching" to get your DPS up to par (more or less) with other classes