Okay, and I will put you on ignore, if you still only answer to the effect of "not really".
The problem is representation. For how it plays out in both chamber and how you elect POTUS. The result is a build in 6% advantage to the one side. Then there is the problem of the filibuster and the more fundamental problem of last past the gate.
Now of course that is no problem for one of the sides and if you side with that one, I accept that. In other words I accept if you answer to the effect of: "I like it as it is".
I think the problem goes deeper and much broader... to me it is obvious that these issues go further than just the obvious. But to first address your points.
1) Yes, representation is a problem... no so much representation and the building of a majority but rather the manipulation thereof. That isn't a constitutional problem but a state problem. Redistricting for the benefit of the ruling state majority, ballot harvesting, lack of voter verification all contribute to the problem of representation. Constitutionally, it is a good mix but locally the abuses are messing the problem
2) POTUS election. I see no problem with the election process (although there has been a few pressing the limit). It will be a problem if one adds to the POTUS for the purpose of dominating the POTUS. That is a possibility and that would be a problem.
3) Filibuster is not a problem but a necessity. It gives power to the minority. It slows government (which is why the originalists sought to do that. To eliminate filibuster is to empower dictatorship of one political party over the other.
For me, and I say again, for me, the problem is exponentially affected by what the forefathers said:
John Adams, “Our Constitution was made only for a moral and religious People. It is wholly inadequate to the government of any other.”
James Madison declared our Constitution requires “sufficient virtue among men for self-government,”... “nothing less than the chains of despotism can restrain them from destroying and devouring one another.”
I think this really expressed the problem... not constitutional but rathe moral. Neither side of the aisle has exemplified morality and thus nullifying the Constitution purpose and capacity.