… he has an american cartoony style but can somehow draw characters who look more human than your typical shonen pretty boy (or girl).
Aldrich, that's interesting – I had the same reaction, but I felt that the series had more of a European style than an American style (The first words out of my mouth after seeing it were: "Sweet!! It's like Kenshin crossed with TinTin!" )
I agree completely about the lack of bishonen and bishojo: I love the fact that beauty doesn't go hand-in-hand with heroism or with evil (that you can't automatically guess if someone is good or bad just by looking at them, as you can with other series). In this one, the bad side has just as many "dogs" as "hotties" – and the good side does too!
Speakng of dogs and hotties : I also like the wide spectrum of attractiveness that Oda presents to us -- how easy and natural it seems for readers to devlop fondnesses for characters with what might be considered "imperfections" in other series : vividly colored hair (Franky, Hina, Vivi, Zoro), prominent noses (Robin, Usopp, Kaku, Laki), curly eyebrows and/or odd facial hair (Sanji, Mihawk, Lucci), oddly enlongated torsos (Nami,Tashigi, Robin), receding hairlines (Ben, Zoro, Khoza, Smoker), tattoos (Nami, Ace, Wiper), horrific scars (Khoza, Luffy, Shanks, Zoro) and etc.
In this way, Oda's world is more like our own : where we see very few examples of pure beauty or pure ugliness, but many examples of the wide range in between.
In terms of non-human character design, I really like the fishmen. None of them look stereotypically (think : Disney) like "mermaids" and yet all seem sound and plausible. I like the extra care that Oda took in giving the bulky fishmen webbed hands or "winged" arms or etc, so that they'd still seem fully capable of swimming, yet also be well-suited for life on the land. I'm looking forward to this next arc, where we'll see them in their natural habitat!