I think not. Although it has been rough this first 6 weeks there are still 10 weeks to go. I am almost positive that Palmer will end up producing some big numbers before it's all said and done. Also, I think injury-wise Plaxico is at a far greater risk of injury due to the nature of his involvement in the game. (Running and catching and getting hit almost every play.)
As far as getting Plaxico and Gore, that is a decent trade. At the very least you may be able to use those players to gain additional trades that will benifit you. Also, you'll have taken 2 great players away from the rest of the people in your league..So, less points for them!
Anyway, those are my thoughts....good luck with the rest of the season.