You still will have to unlearn everything. Martial arts is more about unlearning what you do wrong than learning techniques. It's crazy the number of "extra" things you naturally do when you try to land for instance a simple punch in the most direct way possible.
Another good thing about Wing Tsun is that they acknowledge that their opponents aren't likely to be using Wing Tsun.
This may sound obvious but what often happens in other classes such as with Karate (as an example), is that you have two students practising with each other. One is trying to do a punch, the other is learning how to block that punch. But in doing so though, the other student is learning how to block a
Karate punch. If the first student doesn't throw the correct punch the block doesn't work and the teacher comes round and sees the student throwing a punch wrongly and corrects him.
In Wing Tsun it's all about holding the centre line. The opponent who does not maintain his centre line, will invariably be off-balance and have his organs exposed to your attack.
I'd just like to say, I'm not actually that good at Wing Tsun as it was the last one I started learning before moving and giving up all martial arts, but it is the one that has impressed me the most. It answered all my questions.