You should actually be able to land quite on balance in this stance: get your instructor to check how you're placing your feet. Make sure your knees are bent and you're dropping your weight low, but without bending your knees so low that you lose strength in the stance.
I would defer to someone more experienced than me, but I think of the main advantage of the stance is it lets you deliver power forward from the jump while enabling you to become immediately grounded and mobile. From the x-stop, you can drop back into a sparring stance, or easily turn in either direction, or even rotate through 180 to defend against an attacker behind you.
In the palgwe form I linked in an earlier comment http://www.youtube.com/watch?v=MNkeTjs833I I think the point is that the supported-uppercut finishes an opponent, and the student is then ready to answer an attack from any direction: in the form, it comes from the right.