Governments can already change constitutions? It is just a longer process with more difficult requirements.

To answer the question, I am not sure i am up to constitution making, there is a lot to take into account, hmm, do have an entire year for it, and can probably ask people for their criticism. For the Netherlands, i do not think i will change much, then again, i have not read the text.(I should!)
About the American constitution, people seem to have this whole idiotic romantic view on it, and on how the US govt came to be. For that reason, i would replace it wholly, :P probably with the constitution of some other country. That will force them to rethink things.

PS: the thread has been named very badly...