I am going to assume that MWO uses the same throttle system as previous mechwarrior games.
Sidestepping in a typical FPS is what we normally interpet as torso twisting. Your avatar twists at the hips and moves sideways, his legs pointed in the direction of his movement. In Mechwarrior, we already have that. It's called Torso Twisting.
Juking or strafing would actually be a dash-like action, a true sidestep, keeping legs faced forwards, while making a sideways motion. This is not the normal means of motion for a battlemech, so if used to actually cover ground, it would be relatively slow. At a walk or a standstill, you could strafe side to side to peek out from buildings, to fine tune your position for a parade screenshot, or fine tune your course through rough terrain. If you make a strafing motion while at a run, your 'Mech could use its forwards momentum to make an erratic side-to-side motion. However, if you sidestep too much while running and your pilot can't handle it, you might take a spill.
The ability to juke at high speeds (combined with high acceleration) would give fast Lights some legs when they're running from an Atlas. However, a heavier 'mech would only be able to effect a small sidestepping motion, which might be enough to dodge a little fire, but it wouldn't be leaping over city blocks or anything.
Edited by GreyGriffin, 18 November 2011 - 12:10 PM.