In an ensemble piece, not everyone is going to get an equal amount of screen time, and that holds true for Suicide Squad.
Given that others on Task Force X received elaborate introductions with flashy graphics and flashback sequences, Slipknot certainly drew the short straw in that regard.
Gal Gadot was never speculated to have been on the Suicide Squad set, and Wonder Woman is not mentioned on the extensive list of sequences left on the cutting room floor.
As the third installment of the DC Extended Universe, David Ayer’s Suicide Squad works at fleshing out the world, shining the spotlight on a collection of villains.