I don't use file handling often, but I don't know of a file handling method of deleting a line. I mean, you could write every line after the found line up one line in the file, effectively deleting the line, but that's far from efficient. What's wrong with using /write? File handling has its uses and can definitely be better than /write, but that doesn't mean it's always the best solution to a problem.

Code:
alias Example {
  write -dw $+($2,*) temp.txt
  write temp.txt $2-
}


It really can't get much simpler than that.