Two thoughts on Gordon:
1) I think people wrongly assume that guys can leave the game for multiple years and come back at the same level they had achieved before (see: Aldon Smith, who I'm still rooting for, but who has been invisible for the Raiders through five games). In the narrative of Gordon people also forget that he came back for 5 games and was mostly invisible, supposedly because he never bothered to learn the playbook and simply wasn't even putting in the effort.
2) The era of the Seahawks competing for name FAs is basically over. The only scenario in which they'd sign Gordon is if he made it through the entire FA market without drawing any interest. There are decent players who slip through the cracks in FA every year, but I don't think Gordon will be one of those. He'll flame out somewhere else, IMO.