A. Rod out-homering Soriano is strictly a result of the parks they play in. Over the last two years, Soriano has hit more homers than A. Rod on the road.
I'm not say ing Soriano is a better player. I am saying the difference is only marginal, though. It's a little more offense added to a team that's loaded with offense already.
I can't see A. Rod making a difference. If the pitching doesn't hold up the Yanks won't win. If it does, they'd win without A. Rod.