Visual coding is still in its infancy. We have decades of experience for how to design systems with textual code, and a ton of tools (IDEs, static analyzers, refactoring tools) that work with text.
The fact that some systems are better implemented as text is not an indictment of visual coding as much as it is a testament to the maturity of text as a language for coding.
Game design is only on part of the problem anyway—often a feature which is simple from a design standpoint is complicated to implement in code. This is why you don’t just hire game designers who dabble in coding, but also programmers.