Are there better people, today, who could lead the country? Of course. Will they ever actually be elected to do so? Sadly, no.
America in the late 1700s was a weird moment in history where educated, forward-thinking intellectuals (not nobility, not just the moneyed elite — actually a lot of men who (mostly) deserved to be called intellectual) actually had a chance to make the rules. They made pretty good ones. Some flawed rules, but good ones.
We're not going to get that again. The real-time feedback of TwitterDemocracy would prevent us from ever getting a document as general yet meaningful as the Bill of Rights, with basically unfettered rights to speech and assembly.
So until I see a viable path to put people in charge who actually surpass them in wisdom and foresight, I'm going to stick to what they put forward. It has aged and worked amazingly well, and have 0 confidence that the politicians of today, if starting from scratch, would do better.