EvolutionFist-
Your questions and comments are valid. I understand where you are coming from. Perhaps Ving Tsun is just not for you. That is okay, because not every art is for every person.
I read your post, and I think of the problems with Ving Tsun today. I am no master of Ving Tsun, but I do study it, and I train hard. I am definately not the best either. However, after reading your post, I think perhaps you misunderstood certain concepts or perhaps were just taught differently.
The bong sao (or wing arm)- is a transitional movement to mainly deflect high attacks. The elbow is actually above the shoulder and the wrist is on centerline. The hand is turned inwards towards your body. The arm is held at approx 130 degree angle. You hold no tension in your shoulder or wrist. All of your focus should be near the elbow. Infact your wrist should be loose. You should have a spring like motion if someone were to press towards you on your forearm and then let go. Now when you intercept the strike with the bong sao you are using a bit of forward energy (or intent, or whatever you want to call it - not tension) + your structure to block it. The shoulder should be dropped and relaxed, not tensed or raised at all. That is the hardest part IMHO, the shoulders using the bong sao. Also, remembering not to stay in the bong sao position is hard to. Once you bong, you transition right away. As for the armbar you were talking about, yes that is a very good valid move. It is also very easy to counter. Immoveable elbow theories and dropping elbow are key here. Also feeling your opponet as well. This goes to another principle of the dragon head/tail. When the dragon tail raises (your elbow) the head lowers (your hand) and vice versa. So the moment you feel the chin na being applied you must lower the tail and raise the head, and drop that elbow down. Structurely, the dropping elbow is very powerful.
The fuk sao (or covering hand) is meant to act as a feeler. In VT they say the second hand in the killing hand. That is because a lot of times you want to trap and control then strike. This way you can set up your opponet to put themselves in a bad situation. Now, lets say you are fighting someone who is just really fast. Has really fast strikes. Fuk saos can be used to tell you where your opponet is going before they go there, by feeling where they are moving and how their body moves. Also, if you want to play nice and not really hurt someone you can feel out their movements until you can apply chin na or something else (whatever grappling, take downs whatever). It may not be “wing chun minded” but if it works it works.
The tan sao (or disperssing hand) is used with the whole body. The problem is a lot of people have trouble applying this because they do not use foot work, or positioning. I have found that the tan sao is realistically best for straight punches and it works great. For almost all other attacks I would usually end up using pak sao and biu sao. Or I would use foot work and dynamics to dodge the strike. The tan sao is effective and very powerful structure wise, but to be used in live situations you must use foot work and positioning. Come in at angles, not straight forward on your opponet.
Like I said not every art is for every person. I took several martial arts before I found Ving Tsun (wing chun, whatever) and taiji and I really like them. They are great arts if practiced right and practiced often, just like any other martial art.
Evolutionfist - This was in no way a negative post towards you. Infact I am glad you posted what you thought from your experiences. I too, am interested in other arts and do pick up techniques every now and then from other systems, like animal boxing, CLF, tai hui, bagua, hsing-i, judo etc. Because I am very fortunate in the fact I get to train with a wide variety of people who train different systems. Sometimes wing chun does not seem like it can hold its own against someone who does another art, and other times I win the sparring match easily. I also think mantis boxing is very cool as well.
Good luck in your training,
GFist