Trump's base is shrinking to just the rural areas...

[Wounded Bear]

7. The Senate would be OK without the fillibuster, which doesn't need an Amendment...

That is in Senate rules and is not in the Constitution.

Historically, the fillibuster was rare in the first 100-150 years or so. Looking at pre-Civil War politics, the fear from the South was that the Northern anti-slavery faction would gain a majority in the Senate. Not a fillibuster proof majority, just a bare majority. That's why in the first half of the 19th Century states tended to be admitted in pairs, one free, one slave.

In the modern era, the fillibuster has been used more and more often, until now nothing gets done in the Senate without a super majority, which is very undemocratic.

As to the EC, I don't argue that dumping it is a good idea, it really isn't feasible without a Constitutional Convention. Seems unlikely.