Okay, maybe I should have elaborated more on my "One Piece is realistic" statement…
It's almost just because the people show incredible fraility, it seems realistic. People get dirty in fights, people bleed, and they break bones. In Naruto, they can catch on fire, get mangled up, shot and thrown off a cliff, and still return with barely a scratch save for a cut lip.
When a One Piece character endures pain, you can see their pain and relate to it. Whenever someone get's hurt in One Piece, I literally flinch. When Usopp took that 4-ton bat to the face back in Arabasta, I flinched and almost felt that 4-ton bat crushing my face.
It's not realistic, really. They don't jump around and do flips like most shounen mangas do, which is one reason that it seems more realistic. The characters DO hurt after a big attack. And when they do get up after a humongous attack inflicted upon their frail human bodies, it makes it that much more spectacular.