I agree. I prefer the vast majority of “standard” paragraphs to be the naked <p> and the specials to have the class. Although I also use the more complex css (with appropriate fallback coding) when I know the target device can handle it.
I don’t know that it is “canonical” to not specify indents or line-height at all and leave it to the user to set in their app/device. The flip side of that argument is that some devices/apps don’t allow that setting to be adjusted, so there should be some default…
All I DO know for sure is that I’M right and everyone else is not as good!!