I see DW's decision on draft day 2003 to be reduced to this simple choice:
Coburn as the lower risk/lower return guy vs. Phaneuf as the higher risk/ higher return guy.
At that time, and to some degree now as well, Coburn was seen as a can't miss defensive-minded, not flashy, "will probably be strong defenseman for the next 15 years", guy. Not flash, no big hits just a defensively responsible rock that can be counted on night in and out for 20 minutes/game. Taking a turn on the penalty kill and covering for a more offensive-minded partner. The Thrashers could do a lot worse than 3 or 4 guys like that!
Phaneuf, on the other hand was the higher risk, flashy hits, a little wild and dangerous guy looking to knock out an opponent but occasionally being caught out of position, guy. Some worry (DW) about his defensive positioning. If he develops as scouts expected then he is an annual Norris candidate. But there was the risk that he wouldn't.
One year later, it seems that Phaneuf has developed exactly as the Flames expected and Coburn more slowly than DW expected.
I wanted Phaneuf then and I want him more now because guys with his skill set are very, very rare. I'll take Coburn over the others (then and now) because while seemingly slower developing, will still be a #1 pairing guy for a long time.
DW might have chosen the apparently safer play and missed, but he will still turn out just fine with Coburn.
Now the Valabik story is quite a bit more complicated!