Simple and Accessible
Many literary historians agree that the main reason Thomas Paine's Common Sense became such an insanely influential book is because of the straightforward writing style Paine used to communicate his arguments. And yeah, we know that today it sounds crazy-antiquated an indecipherable. But probably in a couple of centuries everything that we're writing on Shmoop will sound dusty and stuck-up.
Back in the day, Paine was writing for the people.
After wall, it'd be hard to read Common Sense out loud to large assemblies if Paine's sentences were super long and his language was full of dense metaphors. Instead, Paine makes his points with clear, punchy writing, making bold statements like, "The cause of America is in a great measure the cause of all mankind" (I.4). Hey, even that sentence stands up to the test of time pretty well; it's pretty hard to get lost in a statement like that.
It's also hard to disagree with it (rhetorically, in any case) since it's so quick and to-the-point. You'd have to frame your argument as a kind of 18th Century "Nuh-uh. Maybe on opposite day."
And that, friends, is a pretty lame rhetorical style.