Ok, so it seems to me that most people are concerned with the techniques of wingchun. Often times you can hear people discussing strikes, counters, counter-counters, etc.... On top of this many people view speed as an integral part of thier training.
There was a thread last week discussing speed and why it wasnt necessary. After doing some thinking over the long weekend and may be able to explain this better.
Once the gap is closed, you are looking for contact. Once that contact is made what do you do? Do you strike? Do you block? We listen to our opponents. Try to feel their intent their next move. I have read that it is sometimes said wingchun people appear to read the minds of thier opponents and react before they react. The secret is sensitivity. It is my belief that most wing chun people have less then 1% of the sensitivity they could have. Watching some wingchun people spar or chi sau is almost painful because of those infamous flopping arms and the disconnection they maintain to thier opponents touch. Dan chi sau is the very base of this pyramid, but many sort of brush over it in a rush to get to chi sau and sparring. Without it however you have nothing but some flashy techniques! If you train diligently and smartly you develop a sensitivity that allows you to practically read the thoughts of your opponents byt feeling thier tension, even slight tension, and knowing their intent.
This kind of sensitivity allows you to go beyond what speed can give you, it allows you to react on your opponents reactions. Its precision that allows you to strike your target and hit effectively once sensitivity has done its job.