I've recommended the software to my consultant wife (since her company would be paying), but I'm cheap.
How does the pricing work if I want to do revisions to a document? Say it goes through a lot of editing, does each export count towards the maximum number allowed?
If not, what's to prevent users from doing entirely new documents under the guise of "edits" to an old document?
Nope, edits do not count towards the total. You can make as many revisions as you want to a given document. At this point there's nothing to stop someone from doing exactly what you describe. I'm mainly counting on attracting customers that value their time enough that they'd find it silly to expend time and effort gaming that particular system.
I think you're exaggerating the difficulty of your competition. :)
This is a tool for people who don't want to be anywhere near a command line.