I believe the Khan article was referancing someone like markov. Edler isn't worth his price. We are already struggling to score goals and people have no problem throwing tatar + 1 other ready to go prospect with top 6 potential to get him.
Edler doesn't magically turn our offense on. He isn't that level of a puck moving d. The problem for people I believe is they are too impatient to how long it can take to get a d with a similiar level of offensive acumen like rafalski or lidas was. When holland was interviewed shortly after he retired I laughed at how he said within 3 years we would be fine on defense. The best case scenario atm imho is to be patient and let aa, marchenko, xo, and sproul hit the club when they are ready and push out the undesireables (ala kindl, kfq, maybe lashoff but he is a fine 6-7 def d type).
The only harder to trade for is centers. And the type of players often exposed to trade deals aren't the ones 99% of the time the individuals you break the bank for. We missed out on suter and it is a shame we did but we will be much better off "home growing" our defense over the next 2-3 years via established and proven methods of our organization then making a boneheaded freak out decision for a defender. The only way we get a d thats worth it via trade is if there is a "kyle turris" type that says f--- this I want out type deal happening and the likelyhood of that happening is slim to none.