All those names weren't moved out because they didn't fit Bednar's system. They all just plain out sucked, there's a reason why almost every player you listed couldn't crack the NHL again after leaving the Avs. There would be a stronger argument if these players ended up hitting their potential after getting traded from the Avs. But Big Z still shows the same inconsistencies in Chicago as he has here, same with Kerfoot.
You're judging role players by the life expectancy of established top 9 NHLers though. They don't have lengthy careers.
McLeod played two years in the NHL after he left the Avs. Martinsen bounced between the NHL and AHL for two more years after leaving the Avs, just like he did when he was in Colorado. Iginla is a hall of famer and scored at a 26 goal 39 point pace with LA after being traded. And say what you want about Rene Bourque, but he had a relatively good year that season compared to the guys the Avs tried in that 4th line role before. We all thought there was a chance they'd bring him back, but they didn't.
I don't think your point about Z has to do with what I'm talking about. I'm not talking about getting better after leaving. I'm talking about Bednar's flexibility with his system. I'm talking about players who have the wheels and the willingness to skate their ass off, and play a somewhat mechanical system, sometimes at the expense of their preferred style of play.
Zadorov is the best example of Bednar not being flexible. I like Z, but he never fully bought into Bednar's system. He wanted to be a seek and destroy type of defenseman, and that doesn't work with the positioning that Bednar emphasizes from his D core. As a result of that and his penalties, Bednar gave him a very short leash, and healthy scratched him on multiple occasions.
Bednar wanted Z to play like Graves or Nemeth, but Z didn't want to play that way. So Bednar scratched Z multiple times and the Avs ended up trading him, while they gave Graves a $3.16M x 3 year contract, and brought Nemeth back, even though he's a worse skater than Z. That should tell you everything on how Bednar feels about players who either play or don't play the way he wants.
Just saying these guys suck also ignores how quickly the team moved on from the players I mentioned after Bednar got here. This is what proves my point. Outside of Zadorov, none of the guys I mentioned lasted more than one season with Bednar, and three of them didn't even last one season. Even though all of them except Bourque spent multiple seasons with the Avs prior.
If you don't agree with the examples I mentioned, and you think Bednar is flexible with his system, here's a better question. Who are the players that have shown they can't/don't play Bednar's system well, that he and the team have kept around and given a long leash?