Actually the art isnt that bad. the only artwork im not really feeling is Surfer's. Kind looks like he has mittens on lol. Besides that, everyone else seems to be drawn pretty well. In the original Defenders series, everyone wasnt all big and muscular. Nowadays in comics, every hero or villain has muscles on top of muscles, and 8 pack abs.
To me, this what the Defenders are known for. Variety and individuality. Art wise that is. Surfer and Namor were kind of sleek drawn characters with some sort of muscluar tone. Hulk was the ripped one, while Strange looked like a normal man.
I have no problem with the art whatsoever. People want to talk about horrbile art. Read the Invaders series. YUK!