I agree that it's somewhat handled by Greed, but I could also see it as more than that - almost like a multiplier effect. Who would you draft - the 5 tool player who is greedy and has a really tough agent; or the next best guy who is also greedy but has a more team-friendly agent....
I have no idea what coding would be required, although I can already see a lot a negative comments about having agents the same way there are complaints about personalities today
http://1865987047.rsc.cdn77.org/boar...lies/wink2.gif
Given how great and realistic the game is already, it's just another dimension that I would add to my nice to have list!