Re: The type of grading feedback that a computer can give to a student...
Most standardized testing isn't designed to be valuable for the student. It's supposed to be useful for the bureaucracy.
There is something to be said for ignoring simple, rigid rules and allowing some creativity to flourish.
Yes, and there's too little of that even in many college-level composition classes in the US (which traditionally has favored creativity more than tertiary education systems in most other countries). When I taught writing, I advised my students against using style guides, because they tend to lead to undistinguished prose. Richard Ohman's classic essay "Use Definite, Specific, Concrete Language" - an argument against the eponymous recommendation in Strunk & White - does a great job of illustrating the problem.