Surely you recognize that there are two different points in your post.
Corner cutting has always been part of the sport - but the question is when does corner cutting turn into shortcutting (which is a rule violation)? Not only is shortcutting unfair, it is also potentially unsafe and inconvenience to rally organisers (as proved by Mikkelsen's let's-unroot-some-potatoes -shortcut in Poland) who have to foot the bill for damages.
This is a problem, albeit not a huge one. And for this reason, there should be clear, explicit rule that says what is an acceptable cut and what is not - plus what the penalty should be. As it stands now, rally stewards (which do have permanent membership from rally to rally) have to pass sentences without any reference from the rules and hence the varying standards.