You have some good quotes here.

The only one I want to disagree with is this one:
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Wong : “Some students still put too much emphasis on pre-set combinations. Quite often the students already have this idea from books, magazines and by talking to friends. They don’t understand how to apply the concepts of Ving Tsun. This means that the students are concentrating too much on the individual technique rather than seeing the whole situation. They cannot appreciate the theory which would suggest a technique.”
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Pre-set combinations work, that’s why we drill them. It’s good to have a default reaction when we’re defending ourselves because then it will come to us naturally when we need it the most. In a self defense situation, there won’t be time to think about what to do but just react. With enough drilling, pre-set combinations can be done without thought.

This is just my opinion because what we learn in class and techniques we practice, we are never put in a real dangerous situation to maximize the effectiveness of our skills. We can only rely on what we believe works.