I think the OP refers to "flex" and not to "wiggle."

All bikes flex as a function of the frame, and some crank arms and spindles flex more than others.

"Wiggle," to me, means one can, standing beside the bike, reach down with his or her hand and by pulling and pushing on the pedal cause the spindle (the shaft that connects the two crank arms) to "wiggle."

This type of wiggle usually comes as the result of loose bottom bracket cups, and one can remove this type of wiggle by properly adjusting the cups.

As for "flex," which refers to the bending of the frame, the crank arms and the spindle, one can reduce this flex by throwing money at it, but, in the end, a little bit of flex (especially in a steel frame) has some advantages; and, besides, not enough money exists to get rid of all flex (especially with a strong rider).