The more popular the candidate, the greater the danger, all other things being equal.
There’s always the possibility of a “Trail of Tears” episode. He goes off half cocked, the USSC says no (even with the right votes behind it) and he does what he wants anyhow.
But the flip side of popular/populist is that it gives the “We The People” of the Constitution a real meaning again. It’s up to the people whether they want that to be evil or good.