This is what it really comes down to. Whether you're an impatient fan (as many of us are at times) or someone more focused on the bigger long-term picture, you have to be realistic about the return.
Given the huge PR hit the organization just took, immediately turning around and trading the faces of the franchises who are currently in their primes could very easily put you in a situation where you have that shiny new park sitting empty for a long time - whether you're actually trending upward or not. Remember how butt hurt the masses were when Heyward was shipped off? I can remember posters saying they weren't going to the park for a long time over that - and the team had little control left in that instance.
Trading Freddie or Ender for anything less than a King's ransom right now could set the franchise back several years. The teams that have the type of prospects that might equal that King's ransom likely aren't desperate enough to make that kind of move because they have adequate players in those spots as it stands - that upgrade isn't likely to make or break them.