What your family says is true, but "systematic, professional, and data-driven" packages that are appealing to semi-pro or amateur clubs tend to be expensive. To further complicate things, each club will insist that certain specific events be tracked in order to verify that their gameplan is being implemented, which leads to "custom" data that are actually a tagged composite of basic data points.
By the way, thanks for the pull requests on the client. Developing the client and the API backend has been a learning experience at every step, so I appreciate contributions from experienced developers.
I'm the founder of Soccermetrics and the creator of the Soccermetrics API. Thanks for the attention.
I've had the site for a little over five years now. I had been working on data models and algorithms for analysis of soccer matches and thought I would have a go at creating a company out of it. I even applied to YC which was a bit of a laugh in retrospect :) Right now I have another job that pays the bills but there are a few projects I do on the side, the API being one of them.
The API is the latest iteration of my data models exposed to the world as well as my attempt to build as close to a REST API as I could. I don't claim perfection and I'm sure others will have their opinion on it, which I welcome.
I wrote the Python client which is as you say a wrapper over the API, which serves well as a starting point. If you have ideas on how to extend it, please fork and contribute.
There are a few software tools out there that do what you wish. Statzpack is one, SportyBird is another. I have my doubts about how big the market really is for this kind of service, but everyone is very early in this space.
By the way, thanks for the pull requests on the client. Developing the client and the API backend has been a learning experience at every step, so I appreciate contributions from experienced developers.