Part of the reason for this discrepancy in American art vs. Japanese is that traditionally, manga is drawn with balloons fully integrated into the art, from the rough thumbnail stage all the way through finishes, so their design is physically part of the artwork. American comics typically add balloons on top of the finished art during the lettering process, and so are much more likely to make them small and unobtrusive, and not part of the actual structure of the page.

The TP artists so far do a mix of things, depending on what their art background is. Felipe Smith is by far the most grounded in manga out of the previews in Takuhai 1, whereas the rest run the gamut from mostly American comics training, to barely any formal training at all. I look forward to hearing what people think of issue 2 in a month or so. :-) There's gonna be some sweet stuff in there.