The first skill is available at level 20 and is called Shrap Bomb/Corrosive Grenade. This is a short cooldown (12 seconds) skill that has an AoE bleed for 21 seconds, making it a sustainable way to keep objectives from being taken in PvP.
Please think about that one ...
Also regarding your marksman spec in which you don't take the extra 9% cunning...
Another quite useless talent to take is "Burst Volley". Charged Burst is not a skill supposed to be spammed due to weak damage and simple energy waste.
Only way to use it effectively is to proc the 1 sec. activation reduction on aimed shot.
I don't want to be offensive or anything but your so called "guide" isn't much more than weak common sense and simply false facts.