Great idea. ^
Giving a S.O.S card used to be a highlight of a trip for me:
1) I only gave them out when I received great service - that by itself is nice.
2) AA staff were always very appreciative that I recognized their good job - this also made me feel good.
As far as I'm concerned it was a Win-Win program, I was very sorry to see it go.
If AA doesn't bring it back, I think we should start a grass-root S.O.S program here on FlyerTalk. We can design our own "card" with "Bring back S.O.S" and "www.FlyerTalk.com" printed on it. We will make on-line version available foe download (and give the user the ability to have name and AAdvantage number printed on the card) as well as the ability to email the "card" to AA. If AA gets enough of this, they will realize that they need to bring something like S.O.S back.