This isn't directed to you. I'm just using your statement as a lead into a general statement about the entire discussion of "is it the individual or the system."
Depends on the individual and what they want to get out of the system. Not everyone who trains Jow Ga kung fu wants to be able to fight with it. Some people just want to look good doing the forms. Ultimately it's up to the individual as to what purpose the system will serve them.
With that said. There are flawed systems out there. But again. If you want to be a cool stuntman with cool fighting scenes then it's ok for the system to be flawed for fighting yet valid for entertainment.
For example: Gun Kata = Flawed system. But for entertainment. Totally awesome.
Now if you are going to look at Gun Kata and debate if it's an valid fighting system, then my question is why? If you are going to debate if it's the system or the individual that makes Gun Kata a valid system, then my question is why? It would be like debating if an SUV is a valid boat. If people want to debate the statement. "It's the individual not the system" then you must first look at the system and determine what category you are defining.
Are you defining Fighting Systems, Spiritual Systems, or Entertainment Systems.
For example. For every valid Fighting System. It is the individual not the system, that makes the actual fighting valid. Proof of this is that 2 different people can take the same system for the same amount of years under the same teacher and after the same number of training years. It is possible to have one person that excels in the system and the other person that sucks at it. Think of it like tennis. Not everyone is going to be good at tennis no matter how long they train. Why is this the case? Because it's the individual and not the system.
Some people are good at using Aikido to fight with. Why are those people good with using Aikido and other aren't. Sometimes it's the training methods and not the system. Sometimes it's the individual and not the system, like with Rokus. Sometimes it's the teacher, teaching the system in a way that's not valid for fighting. But I can tell you that if the goal is to fight with Aikido then the training will reflect that purpose and a lot of the spiritual context would fall off. Sort of like Tai chi. People who actually want to learn to use it to fight with will have this in their training.
But ultimately it's going to be up to the individual an the path that they want to take. Train it for exercises or train it for applicable use. If the system isn't valid for fighting then there's no need to include that system into the debate of "is it the individual or the system." when it comes to fighting systems. That's just a pointless and it leads to no intelligent benefit. Compare things of the same category within the same Context. Until Chi Ball martial arts train as a fighting system, it should no longer be used as an example of "it's the system." That's just comparing 2 different things with 2 different purposes and functions. An Suv is not a Boat so stop using it as an example of "why it's the system." Compare boats with boats Compare fighting systems with fighting systems.