To be honest, it's really not hard, be more specific than the current class reveals. Example:
Dark Knight, Main Role: Tank, Secondary Roles: Off-Tank, Damage Dealer, Utility, Control. Can use all bladed weapons and shields, uses plate armor. Uses a mix of strength based abilities and intelligence based spells. Focuses on tanking via debuffs and life leech. Can also uses minor control spells such as fear, bind, slow. Can shadowstep to move around, has offensive auras that have negative effects on enemies(Crippling aura, reduces movement speed and attack speed of all units around; Devouring aura, does constant damage and reduces armor of all enemies around you). Special class mechanic: Shadow Armor, the more you get hit, the stronger the shadows protecting you become, increasing your armor and life leech. After reaching the full shadow armor level, you will be able to activate it and absorb the next targetted spell(at you or an ally) and convert it into health. Doing so reduce your Shadow Armor to half.
Then disclaimer about how this shit is early early dev and might not make it as is and what not. But you'd get a much more precise idea of the class, its role and how it plays than the very vague stuff they've shown already, which doesn't even say if Dark Knight is a tank or an off tank or a DPS or can be all of these. They didn't even say if there will be multiple roles for every class or only specific jack of all trades classes.
