According to some recent literature from a large martial arts organization: "Even where genuine material is taught, the style is often limited - the popular Wing Chun is an example. To any hard working student, the entire style of Wing Chun can be taught in two years or less and then you're finished; not to mention that it has serious flaws since Ng Mui didn't have the opportunity to complete Yim Wing Chun's instruction. Also, Wing Chun's weaknesses are against strong attacks to the low gate areas such as iron broom techniques, and against high speed, compound, overlapping circular techniques. And, while Wing Chun talks a good game of deflection blocking and redirectional technique, it is basically a centerline oriented, power on power system any way you look at it."
In our opinion these ideas are caused by looking at Wing Chun as a style. When a beginner first learns Wing Chun, the art is taught in a very systematic, structured way. However eventually all structures become self limiting and must be discarded in favor of the reliance on principles and feelings only. The student must learn to adapt his art to any kind of attack. In an extreme case, we have observed that some hard style practitioners got tied up quickly only because they felt that they must restrict themselves to use specific sorts of blocks which turned out to be too inflexible for close range combat.
To achieve the state of not being restricted by style requires one to give up all ego so that one can react to the opponent. The Wing Chun system cannot work effectively unless it is based on calmness, suppleness and sensitivity to the opponent's movements.
- Ray Van Raamsdonk
The Wing Chun Kung Fu Digital Library