All substances have nonresponders. It's just the way it is. As for arginine, in conunction with lysine it seems to raise GH, though nothing that'll help build muscle. According to Bobo, who I trust, it's good for metabolizing fat over the long term. The pumps most get from arginine are a good mental boost. As to whether the excess blood in the area actually helps build more muscle, that's debatable. I've only seen one study that actually seemed to show the increased blood flow translating into greater amino delivery to the muscle cells.
One thing I'm interested in is a study posted on Haycock's HST site showing creatine increasing the activity of myogenic stem cells surrounding the muscle cells. Trying to look that up on Pub Med to study it further. Not much time though.