Honestly there are a lot of problems with the system in the US, some of which the founders actually foresaw but couldn't agree with how to fix (like the problem with two parties). I'd argue that they did consider voters becoming ineffective, but that's yet another thing they really didn't have a good solution to. In theory, that's part of why the electoral college exists, or more accurately they were worried that ignorant masses would vote in a populist. Ultimately it's been shown that the electoral college hasn't really helped things there at all.

Really it's a bunch of poorly thought out half measures. Like the fact that there's both a Senate and Congress, with Senate intending to represent the "state", which is really just a hastily slapped together replacement for the House of Lords in the UK. In other words, the Senate is supposed to represent the will of the rich "nobility" that run the states, or in the terms of the US at the time, the wealthy land owners (considering how much corporations spend on bribing senators these days it's arguably working, although that's probably not a good thing). Realistically there should probably only be a Congress which is the stand in for the House of Commons and represents the will of the people, although you would need to rethink what kinds of checks you could put against Congress then (maybe a mandatory constitutional review by the courts before new laws can be passed rather than waiting for the law to pass and then having it challenged?).

The entire US government is like a fun-house mirror version of the UK government at the time. The President is a stand-in for the King/Queen, although one with drastically curtailed powers (ironically with the reforms the UK government has gone through since then the President is actually much more powerful than the King/Queen in the UK currently is). Congress is the House of Commons. Senate is the House of Lords. The Speaker of the House is the Prime Minister. The courts run largely the same, although there's some fairly good tweaks there to address some of the abuses that were common in the UK at the time, as well as a couple decisions that have made things worse. Each State functions as a stand-in for one of the noble houses.

Considering modern technology, and the connected nature of the world these days, if we were going to take a second stab at organizing the government I think it would end up looking vastly different from our current system. To start with there would be actual systems in place for the public to censure representatives, rather than relying on their peers to police each other (or at least some mechanism for another branch to punish or remove those that break the laws). Further it's clear the experiment with states hasn't really worked out. Some other mechanism needs to be worked out because the current system causes all kinds of problems and doesn't really solve most of the ones it was meant to solve.