Given the same circumstances, they would make the same document. We have amended the Constitution when necessary. If people cannot understand simple words and they come to diametrical positions using the same words, there is no hope for humanity.
I'd like to hope that they'd (or we'd) come up with a remarkably similar document, but those guys never envisioned the Industrial Revolution. Nor could they.
Things have changed. If someone wants to be a strict constitutionalist and mean it, find where it allows the government to build the US Air Force. It doesn't, of course, having been written more than 100 years before air flight began.
It really doesn't envision a standing army, although you can twist the words to allow it.
I don't know what a new constitutional convention would come up with. I'm about 85% content with the one we have, even though we've messed with it quite a bit.