I believe past is past. The Steelers will lose people they wanted back. They may even cut a few they would have liked back for 2013. They just lose the "insurance" policy and put their faith in the young guys behind them. Really though...It isn't a big deal. It has to happen now or sometime soon.
I think the OP's point is that there is a difference between "wanting" a player back and a player they "would like to have"...
The latter is a luxury...the former is a necessity...
If the Steelers decide that they really want a player, they will work it out...
There are some players that the Steelers want to keep that they will not be able to keep because of salary cap constraints. But they're not going to sit there crying in their beer because they can't get it done...You're not going to hear them saying, "Dang, we couldn't get the guy we wanted, the sky is falling." Instead, they'll get to work and will find other, more affordable players to fill the roster slots. Hopefully, that will yield positive results on the field.
Mike Wallace or drafted rookie
Rashard Mendenhall or Dwyer, Redmond or rookie
James Harrison or Jason Worilds
Troy Polamalu or Robert Golden
Ike Taylor or Lewis (this is probably the only one where the existing option is okay - Lewis)
Kiesel or Heyward/Hood (Kiesel outplayed them both last year)
The Steelers will be releaseing/cutting players because of their salary and the cap situation. I have to believe they want to keep these guys, but the cap situation is going to prevent it. They may try to find a way to fit Troy into the mis, but it isn't going to be easy.