Outlaw = pirate with a toggle aoe button and deadly shot is your waifu ability.
assassination = Hit man with daggers (glass cannon / bursty boi) fairly easy maintain dots, struggles to compete with aoe whereas others can do fairly well in both ST and AOE, small learning curve and mostly requires you to understand openers based on your talent set up.
sub rogue = spooky ninja guy - as for difficulty its near enough a very commitment heavy spec as its the worst spec right now in PVE & PVP