I think everyone thinks because Hightower had the one good game that he is better than Edge. Outside of that game, though, he really hasn't looked very good. He has decent power but he really doesn't have the quickness, agility, or top end speed to make him anything special. At this point, he might be an upgrade over Edge but not by a lot and well, that's not saying a ton to begin with.
As for running when they get the lead, I agree it probably won't happen. Nor should it happen. They could have ended the SF game with a first down on their last drive. On the first play Warner through a pass to Fitz for like seven yards. Then, two runs, no gain, they punt, and SF has a chance... And we all saw how close they came. Bottom line, lead or no lead, Arizona is better off throwing the ball 75% of the time and running the other 25% of the time just to keep defenses somewhat honest.
Arizona's real running game comes from the trickery stuff that they do with Boldin out of the backfield and the short passes to Boldin and Fitz that allow them to use their YAC skills to make things happen.