Unfortunately, it is the nature of man to acquire more power, despite what a piece of paper may say (with all due respect to the US Constitution). Personally, I think it would be best to scrap everything and decentralize government to the local communities.
To the first comment, the Constitution was intended and hoped to be upheld by violence every once in awhile to keep the government in check. When the people lose the spine to do so, the laws of the land as written in our Constitution become invalid. Liberty
must be upheld and defended by by blood if necessary. Our forefathers were rebels and revolutionaries, so why are we not today? As a people, we have lost what it means to be American.
That said, I would fully support some hybrid of the current Constitution and the Articles of Confederation. States would still have to follow the U.S. Constitution and this would be upheld by high courts, but Congress and the President would either be nonexistent or serve solely as figureheads like the Queen of England. The military would be changed as well, individual states being in charge of their own forces unless and until they as as majority felt that a national system of command be formed in emergencies, to be disbanded later.
The problem with the Articles of Confederation is that at the time communication was very slow. This meant that it could take months to assemble a single vote on an important issue even with the Continental Congress. The Articles would worsen this problem, which is one of the main reasons the document was not adopted.
That said, that communication issue no longer exists. If the States felt that, say, the military needed to be mobilized or that war must be declared, a majority would need to support the action. The only federal powers I feel should be in place would be something similar to the Supreme Court without the conservative and liberal bias, and have only those eligible who have sworn a personal oath to uphold the Constitution even and especially in opposition to partisan politics, as well as swear that they, individually as a whole, had no right to officially interpret the Constitution but merely uphold or deny state or federal actions as the Constitution demands. I'd say that this system should be enacted now, but it has become clear that the current Supreme Court has been overruled and undermined by the rest of the government. Our checks and balances now only exist in secret courts and the checking of individual liberties and balancing of the powers of tyranny into a cohesive system.
Our system of government has been undermined at the most basic level, and thus it will take nothing less than a complete reformation of said system to enact such changes.