As much as I'd hate to trade JBJ: he's maybe my favorite current Sox player, there are some aspects that make the idea worth discussion. I'll take "the other side" for a moment:
1) Other GMs value JBJ as much as we do. They ask about him all the time. They'd give something good for 2.5 years of a cost-controlled comodity like JBJ.
2) If we could fill a big need area by trading JBJ, the plus we gain in that area might outweigh the negative we get in OF defense and perhaps offense (hitting & running combined).
3) JD wants to play the OF, and keeping a $25M player content and feeling like he's "in the game" might have some value.
4) If Moreland/Nunez combined are better hitters than JBJ, then trading JBJ could mean an upgrade in offense plus at whatever position we upgrade in the return we get from trading JBJ.
The final equation might look like this:
Con: way worse OF defense by downgrading CF (JBJ to Beni) and LF (Beni to Jmart/Nunez/Swihart)
Plus: Possible improved offense by playing Moreland (1B, HRam DH, JMart LF) & Nunez instead of JBJ.
Plus: upgrade a high need area with the return we get from the JBJ trade.
The issue now is, what is our "high need area?" Do we even ahve one?
1) Farm (Doesn't help us in our current window)
2) Pen? (We have Thornburg and Poyner coming back from the DL and some nice arms in AAA. We also have Johnson, Velazquez & Wright moving to the pen)
3) SP? (We have perhaps the best top 3 SP'ers in MLB and a pretty awesome 4 & 5. Wright, Johnson & Velazquez look like nice starter depth right now.
4) Catcher offense? (Personally, I don't ever worry about catcher offense, if the defense is great and our pitchers are doing great with whoever we have behind the plate.)