Why would you want to rewrite the constitution at this time? I mean there's already something in place, like 0.9999 said. Anyways the Constitution already has its own modkit, it's called the amendment process, so we can modify the Constitution if truly need be; we can even modify previous amendments.
I guess another way to put it is this. I'm a programmer. While I've been pretty unmotivated lately, in my spare time I've been making a game. I've made tons of modifications to this game and it's over 30,000~ lines of actual code. When I first started working on it, I made some horrible design choices. These choices I had to deal with through the whole time working on it, if I didn't have time to fix them. The game still worked but when you're a year into your project it's very time consuming to change all of that. And that's the thing, it's time consuming to actually make that all work again. I could even start it over, like you're suggesting with the Constitution, but it will be extremely time consuming and during that period we're going to get delays and issues and it won't even reflect the modern times anymore. It's going to be so held back that my program is outdated, and thus inefficient. For a game, that's pretty horrible; for a country it's a national catastrophe – at a national level if there is a "bug" in the "System" it could completely crumble the government structure and lead to things such as anarchy or dictatorships.
This is why we stick to an amendment structure, because it is a really bad idea to suddenly shift and restart.
tl;dr if you do this you will make Constitution nukem forever