Fatal flaws? Other than the failure of dishonest people to abide by their oaths, what exactly is fatally flawed about the Constitution? You do realize that there is a perfectly good manner to change any section; it’s called amending the Constitution.
However, no matter if evil people cannot and will not abide by the Constitution.
As for the amendment process, funny that when the patriots fought the revolution, they declared the right to alter or abolish the government. But then when the framers created their own, suddenly we only have the right to alter our government if we can get 2/3rds of both houses and 3/4ths of the state legislatures to agree. Not really in keeping with the Declaration of Independence.