Getting rid of the winner-takes-all approach and going back to a district-by-district approach would fundamentally change the way we elect presidents, and might have prevented Trump; however, it would also change the way in which nominees campaign as well, and we don’t know for certain that another Trump like figure, on the right or left, wouldn’t be able to exploit that system either.
It is also important to keep in mind that the framers did not intend to have the sheer number of people who are eligible to vote to do so. They very openly envisioned a system where the ability to vote was restricted to a much smaller class of people, which would exclude the majority of the population today.
Given that we have tended to move toward a more open election process, or at least the perception of openness, to return to the built in safeguards proposed by the framers would need a lot of political capital. We forget about the Electoral College, generally, after the election, especially if it aligns with the popular vote, so to return to the system where it is much more explicitly stated that a separate group of individuals are really the ones that elect the president rather than rubber stamp the who the majority of their state voted for, would strike me as very odd. Not necessarily bad but it would require a much larger campaign about why this should be a two-step process, unlike most other elections, for example for governor.
