I assume you are talking about the WC guard like this, One arm almost extend and another hand is next to the elbow joint. IMO, if the back hand can move to the wrist area (similar to the rhino guard), the back hand will almost have the same reach as the front hand, that will solve 1 long arm and 1 short arm problem.
This traditional WC guard can protect the chest area more that the head area. It's not like the boxing guard, or the rhino guard that you can hide your head behind it. So when your opponent attacks your head like a mad man, this traditional WC guard won't do you much good.
There are only limited number of effective guards:
1. Boxing guard that both hands are close to your head. You protect both sides but leave your center open.
2. WC guard that has 1 hand near by your opponent and 1 hand close to yourself. You protect your center but leave both sides open.
3. Rhino guard that has both hands near by your opponent and you can hide your head behind it. You protect your center, at the same time you also protect both sides.