I'm not disputing the fact that they took ideas directly from the British government. I disputing the fact that it was done without consideration, reform, or reason. There's ample evidence that they heavily debated each part of the British government that they adopted.
The fact is, the founders remedy for a corrupt president was impeachment. They made that perfectly clear. Corruption included things like misusing the pardon power (High crimes/Bribery).
What they didn't anticipate was the fact that we'd end up with a 2 party system equally spitting the country where neither side would remove their president from office. The put a LOT of faith in "honor" and the fact that the general electorate would punish dishonorable leaders. They did not expect things like wedge issues.
Isn't this true of your own original post?
I don't really understand what argument you're trying to make.
The British system was very familiar, and while it had potential flaws visible to them at the time they were known familiar flaws. I find it doubtful that someone coming up with an entirely novel and unfamiliar system would have got anywhere at all, no matter how rational and well argued it was. People like familiar and that can affect their judgement. Just worth considering.