The Wildcard system is a new addition to the Call of Duty series and is designed as a part of Black Ops 2's Create-a-Class system which allows players to design their own characters with perks, armaments and so forth.
Unlike previous systems, the Create-a-Class system in Black Ops 2 is point-based. Each item, be it a perk or a mod for your primary weapon takes up a point. This allows the developers to balance the game around individual items instead of ensuring that each weapon mod is equal to the next, for example.
As weapons can only equip two mods, players must use a Wildcard called Primary Gunfighter which allows them to equip an additional (third) weapon mod.
Attachments do more than simply provide a small bonus to your weapon. Unlike Black Ops, where having three attachments for your gun wasn't all that important, the Sleight of Hand perk from Black Ops can only be found in Fast Mags, and Steady Aim is now called Laser Sight, both of which are attachments for your primary weapon.
Here's a list of all the Wildcards available:
Primary Gunfighter – 3rd Attachment for your primary weapon.
Secondary Gunfighter – 2nd Attachment for your secondary weapon.
Overkill – Equip two primary weapons.
Danger Close – Secondary lethal grenade.
Tactician – Equip an extra tactical grenade in place of a lethal grenade.
Perk 1 Greed, Perk 2 Greed, Perk 3 Greed – These Wildcards allow you to equip more than one perk for the specified tier.
