Wild Swing is an attack option toward side and rear hexes in Basic Set: Campaigns pg 388.
It cannot be combined with the Determined option for All-Out Attack per Basic Set. It might possibly stack with Evaluate bonuses though since that is not singled out and IS present in basic set. The new options of Committed Attack and Telegraphic Attack from Martial Arts have not been mentioned in association with it.
Wild Swing is a natural combination with Move and Attack because the penalties do NOT stack: one simply uses the WORSE of the two.
"A Wild Swing is at a -5 hit penalty, or a maximum attack roll of 9, or the current Darkness penalty, whichever is worst."
Elbow Strike and Back Kick (B230) were alternative options which were not as heavily penalized.
Back Strike was added in MA to further add options.
B548's within 1 yard rule less harsh: only -4 to hit. It's unclear if that might be a typo, a reduced penalty for wild swings done at close range, or intended to stack.
"cannot make a “wild thrust” at a distance of more than one yard." implies a wild swing could be made at distances beyond that.