The concept of "checks and balances" is pretty astute, I don't know how else things could work well, though some other countries have of course different ways of doing things. The concept of "innocent until proven" is another great concept. Trial by jury, I never thought up another good way to do that.
The Supreme Court basically cemented its ability to overturn decisions and interpret law at Marbury-v-Madison. We owe a good but I think to John Marshall for his prudence, and juriprudence, most decisions then were 6-0. Did you know more SCOTUS decisions in the recent term were 9-0 than any other vote? That has been true for a while also.
The concept of a Senate is good, I think, though one can certainly argue the compromise on its structure is ... debatable. The concept of the Electoral College has strengths, and weaknesses, like most things. Democrats don't like it, Republicans usually do, because it favors or disfavors their strengths. No need to get into them, the EC isn't going away, though the Compact of the States could change things without an Amendment. Maybe.
Can you imagine California voters learning their electors voted for Trump? Ha.