>>50576093I can answer that actually
Essentially in the original script(NOT the one that aired, but one that was scrapped in preproduction), Goh was going to do Pokemon GO stuff; the Team Valor lady was his older sister; he had an inferiority complex to her because she was so good
So basically he joins Team Valor (you can see the unfinished Team Valor base/gym in ep 3) and does missions and shit
The catch every pokemon and catching sprees were added as a stopgap in the new script because they didnt know what to do with him; served as both PoGo promotion and filling mon quotas
However, fans naturally hated it, and one of the mandates Owada had when he took over was clearly to give Goh a clear goal, hence Project Mew