I would never consider any MA bad. It only becomes "bad" when people make silly excuses for its absence in MMA/NHB, or when they develop ridiculous methods like "anti-grappling" instead of simply pushing their students to learn Bjj or wrestling. Saying that your art wasn't made for sport, and that you can stop grappling with dick grabs is dangerous and setting people up for serious problems down the road. The simple reality is that your art has a deficiency that it needs to fill. All MAs have them, but not every MA goes about it in the right way for whatever reason.
BTW, it's interesting that Juany points to Bruce Lee as an example of an effective WC user. Lee threw WC (and Kung Fu in general) under the bus as he became exposed to more fighting methods in the US. He became a pretty big proponent of boxing and various grappling methods, and tossed kata/forms out of the window. In short, he personified what the entire MA world experienced after the first UFC in 1993.
No I didn't point to him as an effective Wing Chun user, only that he is associated specifically with the Art.
Here is the problem. Bruce Lee really didn't know Wing Chun completely and, it's Ip Man's fault. (Heresy time). Why Ip Man's fault?
1. He was traditional and refused out right to teach to foreigners. Lee was half Caucasian and it is not unknown that this made Ip uncomfortable.
2. Ip Man's teaching style was equally traditional. He basically showed you technique once, used few words. You got it or you didn't. He was happy to answer questions, it showed the student was engaged BUT not questions? One and done AND that was if you were lucky enough to have him teach you. Most of the teaching, when Lee joined the school, was done by senior students.
These alone would create issues. Add to the fact Lee studied Wing Chun from 1956-57 to 1959 before his parents sent him off to the US because the cops kept showing up at their door because of all the fights he was in, you have someone with incomplete training, by no fault of his own.
Lee was incredibly gifted physically but he simply didn't know enough about Wing Chun. It's even evidenced in his critique. He said Wing Chun has only one range. Not true, yes the bread and butter of many lineages is close range but it has all four ranges he said made JKD different (long/kicking, medium/punch, close/trapping, and yes grappling range, Wing Chun has Chin Na, heck it even teaches ground fighting defense it's just usually taught later once you have the first three down. Now please note this is from my experience, the Wing Chun I learn, is Ip Man lineage via the not uncontroversial Grand Master William Cheung line) . Second that Wing Chun is static and lacks mobility also not true.
This is not a critique of Jun Fan Gung Fu or JKD btw. Only that sometimes you can come up with good ideas and results from a spark born of a false premise or assumptions born of the fact you don't realize your knowledge is limited.