Rogue
The wound is the least of your worries.
Shiv - Rank 1
Requires Level 70
Variable Energy
5 yd range
Instant cast
Requires Off-Hand Melee Weapon
Performs an instant off-hand weapon attack that automatically applies the poison from your off-hand weapon to the target. Slower weapons require more Energy. Awards 1 combo point. from [1]
The energy required to use Shiv is equal to
(20 + 10*weapon speed)
so a 1.3 speed weapon would require (20 + 10*1.3 = 33) energy, whereas a 2.9 speed weapon would require (20 + 10*2.9 = 49) energy.
Uses
While at first glance, Shiv may seem like an underpowered attack ability, it was several unique properties that make it very useful to smart Rogues.
Poison Application
One of the most obvious advantages of Shiv, instant perfect poison application is useful in a variety of ways:
- Stacking
[Deadly Poison] for easy 5-pt, 5 poison stack 
[Envenom]. - Application of
[Crippling Poison], [Mind-Numbing Poison], or stacking [Wound Poison] in PVP. - Application of [Instant Poison] or [Anesthetic Poison], to mitigate the loss of dps over other skills.
Combat Potency
Shiv attacks do proc 
[Combat Potency]. Spamming Shiv with a high-dps offhand with a speed less than 1.5 (costing 35 energy) can be very effective (given 1x 20 energy tick and a combat potency proc for another 15 energy). The high special-attack rate this skill and talent synergy has other benefits- more hits means more chance on hit procs from gear, more mace spec procs, and any other goodies you have.
Energy Cost
With its relatively lower energy cost, shiv can build combo points very quickly. Useful for fast stuns, or when you need to get 
[Slice and Dice] up.