I know what you mean, but I'd argue that the balance of powers principle in the US giving the president so much power has done the opposite of what it's supposed to do. Instead of the executive being restrained by the other branches, it has completely taken over them because the other branches are worried that they would lose too much by resisting.

Whereas in a PR parliamentary system, it is extremely rare for any one party to have a majority, so they need to compromise with other parties to elect a prime minister. Even during war time, it's common practice to use a unity cabinet that includes all major parties. The judiciary seems to be more independent and can enforce the basic law. Also, 50% of MPs or the president/king can call an election at any time if the PM is getting too spicy.

Tyranny of the majority is tricky though. Most of the responses to that seem to be devolution or international cooperation.