I was just wondering if this would be a different discussion if Holian had asked about two other players. Say: "Is this club a Terrell Owens (or Eric Moulds or Randy Moss or Marcus Robinson... er... Chris Chambers) and Jamie Sharper (or Peter Boulware or LaVar Arrington or Jamir Miller... er...or Terrell Suggs... er... ) away from a serious playoff run?" If you frame the question that way, I'd have to say no. There are too many holes on this team that a couple of FA acquisitions would be able to fix. I think the point is that getting (or retaining) a couple of players of this caliber not only make the team better, but provides a psychological boost to the players and fans that can't be denied and definately contributes to a winning attitude in September through December.
I think that obviously this squad isn't "on the cusp" of becoming a legitimate contender for a Super Bowl. But the secret is drafting well and holding on to your best players. When good, developed players (i.e. Miller, Rice, Boston, Plummer) leave without compensation, you have to invest picks to replace them, and there's more risk of those picks not panning out or approaching the level of their predecessors, and you can't improve other positions with new high draft picks, and so you're plugging holes with Undrafted Free Agents and lower-tier vets Free Agents.