Y'know, I still don't think so. I agree with the running to the Whomping Willow as a stag because it's faster, but stags are big, and all the descriptions we get of that tunnel are that it's small, as I recall. Yeah.
They moved as fast as they could, bent almost double....
Prisoner of Azkaban, page 337, American edition
If they had to bend almost double, how was a great big stag going to charge down that low tunnel and then get around Snape, and then drag him off? I bet if he had to, James was willing to use magic to make it easier to get Snape out of there before the werewolf noticed them. I think he'd only turn into a stag if he had no choice and then get between the werewolf and the person, since it does say that animals aren't in danger from werewolves, only people are. That was how the Marauders were safe in the first place. But it seems more like a last-ditch option to repel Remus's attack on them with his stag form, and the human form still seems more useful to me for getting Snape out of there.