I think we have a similar way of thinking. I once wrote a blog post about a for loop extension (based on Golang for illustration) [0].

  values := []string{"hello", "world"}
  for v, value := range values {
    fmt.Printf("%s", value);
  }
  inter {
    fmt.Printf(",")
  }
  before {
    fmt.Printf("[")
  }
  after {
    fmt.Println("]")
  }
  empty {
    fmt.Println("(nothing found)")
  }

[0] https://lukas-prokop.at/articles/2024-04-24-for-loop-extensi...

And which blocks of Unicode exactly would you exclude from support and what complexity reduction do you exactly expect from it?

In my experience, the complexity comes from the reality of how we write in different writing systems. I think this is inevitable.