Before saying anything, I'm Canadian. My constitution received its last major update only 30 years ago, and yet, I have no idea what it says. I don't know a single person who knows anything about the Canadian constitution. Americans are the only people who seem to think that the constitution really matters.
Anyway, gun laws. The constitution was written when knives were a better alternative to guns, because guns couldn't kill anybody, much less the crowds you can gun down with modern weapons. The founding fathers clearly didn't intend for weapons of mass destruction to be legal.
The United States does need to be changed for several important reasons.Many of the articles and amendments can be seen as being outdated especially the ones related to voting and the Electoral collegw with does always reflect the way the overall population would choose to vote if they were given the choice.
In my opinion the United States Constitution should be changed to reflect what the founding fathers originally intended. That corporations were tools of the people and should only be formed when absolutely necessary and disbanded as soon as feasibly possible as well as the courts having the DUTY to do away with any corporation that was not acting in the best interest of the people of the United States.
Constitutional amendments in Australia require a majority of votes in a majority of states and that requires millions of dollars worth of government funds. Instead, simply let the courts ignore sections of the constitution that have become outdated and legislate accordingly. It is easy to change legislation, but the amendment of the Constitution is a massive decision that should only be reserved when there is confusion in the right to legislate or in other exceptional circumstances.