Our asset base isn't strong enough for us to start trading our most valuable assets. Our biggest weakness IS our asset base, for now. It still needs to be shored up before we go down the road of trades, where your asset base doesn't really move. Just displacing one hole for another. Or more likely, overpaying to get a specific player, shortening our asset base. We just aren't there yet, and if we were to go down to that road too quickly, I foresee a future middle of the pack team where we'll always be short somewhere because we didn't stack long enough and don't have the ammo to make the team truly great.
Now, I'm not saying there are no trades to be made, but simply that we still don't have the horses to think sideway moves (in terms of asset base) will fix our biggest holes. In all likelyhood, we would be giving up more to get specific players. We're just not there yet.