I could also be wrong. There have been cases of both. Sometimes a player gets a change of scenery and is the same guy he was in the last place. Sometimes he revives his career and finishes out with that team a fan favorite. I don't think Shockey has done such horrible things ala a Chris Henry that we should totally write him off.
I see where some are coming from with the distrust of having Shockey come on board but I personally think its worth the risk. I see Shockey coming in and being one of the very best TE's in the NFL in our offense.