There are two ways of looking at this. In the US system (because of all the lawsuits), the law tends to be very objective: cross all the i's and dot all the t's and you demonstrate compliance without regard to intent, for the most part. The letter of the law is seen as primary.
Many other places use more subjective concepts and rely on the intent of the law more than the letter of the law. This can be problematic in court, because subjectivity enters into the discussion. It is hard to prove intent, a person's subjective rationale.
A term such as "unconscionable" is very subjective. Who decides what is "unconscionable"? It goes, pretty much without saying, that the person who performs such an act does not find it so, or most would not do it in the first place. So, who decides, and what is the line between conscionable and unconscionable? How can we say where and when that very vague line is crossed?
Does a system using one, or the other, concept suffer? Well, sure, both sides can see situations where the system fails. I don't see a solution though. You either allow arbitrary judgement or you impose strict criteria that must be matched, and in either case, there will be people who get around the purpose of the law. Both are imperfect.