Holmes will be the starter as long as he is healthy. There's a nice little bandwagon starting on the Steelers suddenly becoming Air Tomlin. I see a slight uptick in the passing game over last year, and remember that the numbers were inflated somewhat last year due to the Steelers playing from behind most of the first 8 games. However, a realtiy check here is that Willie Parker and Hines Ward are still the first options in this offense (Ward arguably wasn't 100% all season last year), and the Steelers may go to more 2 TE sets, especially in the red zone with Heath Miller and 6'7" Matt Spaeth. I like Holmes, and he COULD be a solid #3 fantasy WR, but he also could end up near the waiver wire in terms of production.
We hear the talk, but it's not clear exactly how significant the changes might be with the Pittsburgh offense.
Even if they want to become more pass-friendly, there's no guarantee of success.
As a Steeler fan, I want to see it work out. I think Ben has the talent and the competitiveness to shoulder the burden of becoming more involved with the offense. He performed well in a pass-first offense in the 2005 playoffs (except for the SB). Yet until he does it for a full season, he's still unproven in this role, so until then there's a a possbility of overestimating Ben, Hines and/or Santonio as a FF producer for your squad.