No doubt they need to be better in a variety of aspects, but they usually defend by winning battles outside the slot and getting the puck out. I argue that they did a whole bunch of other things wrong long before the puck ended up in the slot area for a lot of those goals. Way too many board battles lost, especially by #s 24 and 27, not to mention some insanely dumb turnovers by a LOT of players, not just those two.
Yes, the slot-area defense needs to improve. My point is that is not the root issue.
I see what you're saying, but I think adding a defenseman that is good at defending the front of the net will help with some of these other areas as well, like winning boards battles, and hopefully less turnovers, because they're rooted in the same problems.
There isn't anything inherent about a team's system that makes them better or worse at defending the front of the net. Whether you're good at it or not is almost exclusively a personnel issue, because all teams more or less approach it the same way.
Vegas leaned on Pietrangelo and Martinez to deal with these situations. The Avs leaned on Graves and Nemeth. That's a big difference.
The Avs also had smaller guys like Girard and even Toews who are great at what they do, but can be exploited easier in front of the net. The Vegas defenseman are bigger than the Avs so they're better at defending the front of the net, but more susceptible to being exploited off the rush or cycle with the Avs speed.
But Vegas did a much better job mitigating their problem by clogging the neutral zone and winning battles to prevent the cycle, then the Avs did at mitigating their problem with their smaller defenseman defending the front of the net, or winning physical battles to prevent the Knights cycle from keeping sustained pressure in the zone, or capitalizing on their chances in front of the net.
Vegas can use their system to help with their problem, but the Avs can only do so much system wise to make up for smaller or worse defenseman having to cover the front of the net, because those net front situations are going to happen no matter what you do or what system you have.
The Avs don't need to change their system, or their style of play, and they don't necessarily need to give up smaller guys like Girard if they don't have to.
What they need to do is make sure their bigger defensemen are better defensively than someone like Graves or Nemeth, so they can play this role effectively, and if Graves/Nemeth are still here they can play a smaller role where their deficiencies aren't exposed as much.
It would be great if EJ could stay healthy enough to do this in a top 4 role next to Girard, but even I can see that it's too big a risk to rely on him for that because of his injury history. He can just be an added bonus if he's healthy.
So if they have a Cup favorite team with only a couple more years with a cheap MacKinnon, they need to make sure they address that weakness they have, because there's a pretty good chance they'll have to go through Vegas next year in the playoffs too. And maybe the next year after that.
I'm expecting Colorado-Vegas to be the next Colorado Detroit/Dallas. They'll have to go through each other to win the Cup more often than not the next few years or so.