The Berra trade wasn't as bad as it seems on paper. The Avalanche gave up the 54th pick of the 2014 draft. One thing to consider when evaluating that trade is that the Avalanche's drafting had been mediocre up to that point. They fired their head scout after the 2014 draft. That was the same draft that they wasted a first rounder on Bleackley. It is much easier to move a 2nd round pick when your team has a bad draft record. Odds are, Colorado got more out of Berra than they would have out of that 2nd rounder.
Also, Colorado saw potential in Berra, he had a history working with the Avalanche's goalie coach in the off season. So it wasn't as cut and dry as giving up a very late 2nd for a backup goalie. It didn't work out, but he had some bright points.
The Stuart trade was a steaming pile of ****. I'd like to think that part of the reason San Jose paid such a steep price to trade up a few spots and get Jeremy Roy was because they felt bad about fleecing Colorado in the Stuart trade so they gave them back their pick. If Stuart was what Colorado thought they were getting, what they gave up would have been more than fair, but he wasn't.
Evaluating their other trades, the Tanguay trade worked out pretty well when you consider the players that went the other way and that it was mostly cap in/out instead of them actually "buying" Tanguay with assets.
I didn't like Downie for Talbot at the time, but there were rumored off ice issues.
The Briere trade was a good move. It ultimately worked out to paying MTL a late draft pick to take on an extra year of what turned out to be a bad contract.
Their trade deadline moves this season were fine. They got hustled a bit on Boedker since Arizona pimped his numbers with significant PP time, but a 2nd and a B level prospect wasn't a lot to give up for a rental. Obviously, it looks bad now because they missed the playoffs, but if you're a fan of a team that was in Colorado's position at the deadline you've gotta be happy about them doing what they can without selling the farm to try and improve the team.
I still think both in the short and the long term they lost the ROR trade BUT before I get jumped on, they got a very good return when you consider the context of the situation. It is just very hard to move on from a player of ROR's caliber. I'd rather have ROR+2 way bottom 6 forward than Comeau+Soderberg at 8M, but I can see the argument about how signing ROR to such a big contract could hurt the teams ability to enforce a salary structure and get players to buy in on taking slight discounts like Johnson and MacKinnon probably did.
I think there might be an issue with Colorado's ability to evaluate players at a pro level which has caused them to make a few bad trades or sign UFAs to contracts that with the benefit of hindsight aren't the greatest. This isn't to say they haven't found some gems in free agency like Beauchemin who they got a lot out of this year.
The Avalanche haven't done that bad with trades, but I think part of their reputation as being bad at trading comes from the fact that this regime has yet to actually make a real blockbuster trade where they aren't the ones selling off the superstar and instead are the ones buying one long term. As a whole, they haven't made that many awful trades. The only really bad one was Stuart. The negative is their heavy reliance on UFA contracts for non-core pieces because they haven't developed 4-6 level defenders and middle 6 forwards due to their bad drafting which has made them more susceptible to having bad contracts than your average team.