Jesse Glover was great at what he did, so was his brother Mike! Saying it was very crude and basic is not putting it down in anyway it is just saying what it actually was and very limited stuff too. Bruce Lee did not know the full Wing Chun system > Jesse Glover did not learn from him absolutely everything Bruce Lee knew in Wing Chun > Jesse as he stated himself adapted it to work for him and what he felt best would work for others nothing wrong with doing that. The material Jesse Glover, Howard Williams etc learned was very limited indeed that doesn't mean it was not effective or that you need more material to be effective. Such people spent the rest of their lives practicing and refining those basics or limited amount of techniques they learned, which is highly commendable. Regarding the limited nature of material, here is Lamar Davis on his experience of Howard Williams material :
''In 1998 I sponsored a seminar with original Bruce Lee/James Lee student, Sifu Howard Williams. I had heard many good things about Howard over the years, and had spent many hours talking to him on the phone about his experiences with Bruce Lee and James Lee, or Jimmy as he called him. I was really expecting great things from the seminar. I hate to say that I was more than a bit disappointed, as were the participants of the seminar. There wasn’t much material shown, and after one four hour afternoon of training, Howard had nothing left to teach the second day. There were a lot of complaints about the seminar, and several participants told me that if I had him back for another seminar, they would not be attending. This had only happened one other time with a seminar instructor, so needless to say, I was quite embarrassed for Howard. I never saw him again after that event, and he passed away a few years later.''
More techniques or material doesn't necessarily mean better but often limited material cannot deal with all combat situations or there are other things or training methods that can enhance your core techniques. Also if people using that limited material are only or mainly training with their own guys doing the same things...........
Here is Mike Lee, Jesse's brother :
Is that material Mike's doing crude and basic? Very much so, that does not mean he could not use it effectively.The power shots are telegraphed by a mile, etc.Mike probably trained harder in weights, cardio, strength training, fitness etc than Jesse did, doesn't mean he was better than Jesse both were great! Both were big guys and powerful. Bruce Lee refined & modified things greatly later on, had he worked with Mike Lee (as you see in the video above) in the early 70's of course he would have refined things, showed modifications and new material.
Jesse's trapping was very crude that is not a put down or insult, he wasn't an athlete of Bruce Lee's level, he did what worked for him & modified it to be used by anyone. Bruce Lee did not know the full Wing Chun system, what Bruce did know Jesse did not learn all of it. In Chi Sau he learned limited material, attacks, counters, positions, etc > compare to a Wing Chun Masters Chi Sao that knows the full system or to Dan Inosanto's. Someone can practice the basics and limited attacks, counters etc and become very good at it - better to do that than learn lots more but not be too good at any of it or not practice it extensively. With limited Chi Sau, you will find the best Wing Chun people have attacks and counters etc you do not know and that you have no defence for.Jesse was right some Wing Chun people aren't that good even Masters but for certain there are some who are! Dan Inosanto has had nearly 10 Wing Chun Master teachers instruct him, he's trained or trained with nearly all well known Bruce Lee students, he was with Bruce Lee the longest and the only one allowed to teach by Bruce Lee (Chinatown classes), he has also met many people from the earlier period before he met Bruce and seen what they know and can do including Jesse, he also knows how Bruce modified things & why he did so in Chi Sao, Trapping etc.If you practice Non Classical Gung Fu as Jesse termed it, someone like Dan Inosanto can improve your skills and show further material that will enhance the skills you already have, he can show why Bruce modified things and why he discarded certain things. Dan is modest but he is obviously better than Ron Balicki, Paul Vunak, etc at trapping and they are all very good at it, Ron etc would have no problem saying Dan is in a different league from them. Bear in mind Vunak met and trained with Jesse Glover,William Cheung, etc and Ron Balicki was also a student of renowned Wing Chun Master Randy Williams.
If you choose to do only or mainly the early material Bruce Lee taught, you can for sure develop high skill level with it and be able to apply it. No doubt Jesse and Mike Lee were very skilled at what they did, they were both big guys physically stronger than your average person and could pack a punch. Though there is a wealth of material out there that can enhance your skills and you are free to select what you add or don't add. Jesse, Mike Lee's, Howard Williams, etc striking, Chi Sau etc was very crude and basic again not an insult at all they did what worked for them and what they felt could be used effectively and taught to others.