Why are you interpreting the law to solve problems? Activism? The court is not a super legislature. As has been mentioned several times, an amendment process exists, and has been used. I would argue that 90% of the Constitution is quite clear and applicable. There is no need to stretch its meaning.
Interpreting the law to solve problems is exactly what the courts were intended to do. SCOTUS settles disputes that are inevitable in law. The problem I has is that the circumstances we find ourselves in (or at least the matters that the SCOTUS has to deal with) are so far removed from the original document.
Just got an alert on my phone about the census case going to SCOTUS. Trump wants the Census to apportion seats by legal residents and exclude illegal immigrants. Okay. What does the original document have to say about that? Nothing. Know why? Because there was no such thing as an illegal immigrant in 1787. The entire concept of an illegal immigrant didn't occur until about a century later. Original intent cannot be used to determine the outcome of this case.