If you trade Dunn, you're eating $$$ (which the Sox fucking hate doing), and the return is going to be minimal.
If you move him now from some random replacement level (or a little better player), you're still paying at least $7.5M for Dunn and you take away our only real home run threat, as of now. Too early to judge Abreu, Davidson. De Aza and Tank can swing 20ish, but not the 40+ potential Dunn gives you. Also; Paulie sucks now.
And frankly, as much as people hate Dunn, his absence probably hurts the team more than it helps.
Best case scenario for Dunn haters is that he has a monster first half, and you can move him at the dead line, unless the Sox are some how in the race. Which, is probably unlikely.