I traded for Luc for my 3.09 pick because I thought I was a good value and I could trade him later. I shopped him around for a goalie, but there were no buyers. Any goalie I wanted was already gone by my 3rd pick, so when it came down to the 5th, I was willing to let Roby go for Chevy because I wanted a goalie. Would I rather have Robitaille & Casey, or Zhamnov and Cheveldae? I chose the latter, given I had two strong F anyway.
The point is, I can tell a story here, and people can follow. I also didn't think it was as lopsided as smoz's calcs. With the Mogilny trade, it doesn't make sense. Carson, Shanahan, Francis are all close enough, interchangeable based on what someone wants. Mogilny however is in another league and I can't understand what was gained to Iceguy with this trade.
I think Sicarius' use of overall numbers shows the value point clearly. (ANY rating system would have Mogilny rated waaaay higher than the other 3). The other point is there is no explanation for this trade (i.e. swap forwards for defense, size for speed, etc.)