I think that is the big mistake that is made when applying the punches of WC. Most want to stay at a boxing range and hit only with their arms...this can be very easily dealt with by an opponent.
When performed properly, you are hitting with your whole body...the fist is just the delivery system....this is not so easy for an opponent to deal with.
This is why you see boxing dominating novice Wing Cun guys so often. It's hard to get past that range without eating a few... Chain punching for me is also the linking of punches. Not the bicycle punching you often see. It can be any number of punches. It can be performed at different levels, from high to low, with even a circular huen choi thrown in here and there.
I take you mean the circular swingers with no particular accuracy. Larger males tend to use it. Have you tried chain punching while targeting an opponent downwards. IE, they could be crouching down for example?