So what put me on this thought train was actually talking with some Ducks fans about Gibson and how he has really been their MVP. I made the point that if their defense was so good, why do they need their goalie to stand on his head night in and night out? The point was made that the talent is irrelevant. Particularly, it was this comment that got me thinking (Hope it is ok that I quote you @HanSolo ):

https://hfboards.mandatory.com/threads/john-gibson-41-save-shutout.2553005/page-2

"It's because a defense is more than just the level of skill in the guys playing on the blueline. The problem isn't that Anaheim's young blueliners aren't as good as people think. The problem is Carlyle's defensive systems are stuck in the past and he doesn't hold his forwards accountable for half assed defensive efforts."

I cut the quote off here because this is the relevant part. Defense is more than just the level of skill in the guys playing. It is a system. Then I started thinking about other teams that have good defense but don't see the results.

Calgary - In the bottom half of the league for GA last season despite having several very good D.
Carolina - Again, in the bottom half of the league despite good D.
Tampa Bay - Stacked blueline with a really solid goalie, yet middle of the pack defensive team
Columbus - Only 2 less goals against than Toronto despite having a Vezina goalie and a stacked young blue line

Then I started thinking about the opposite

Vegas - I really don't think their D is that amazing. Yet they were a top 10 defensive team last year
Dallas - A team known for being really poor defensively got a defensive coach and the defensive issues went away

Even some other teams who had the least GA had goalies who faced a TON of shots against like the Jets for example.

So my question is - HOW much is the game about how TALENTED the defense is, and how much is about the SYSTEM in place? With Forwards, they are either good or they are not. It is very easy to see their talents and abilities. I don't feel defense is the same way. Using Toronto as an example, their forwards blow the zone right away and when you watch a team like Boston, their forwards play way deeper in the zone and give puck support to the defense.

How does this impact our perception of talent? Are we more biased to say that a team has a better defense when in reality, they play a system that actually supports the D? How do we differentiate the difference between talent and system?

I feel the ultimate example of this is Dallas.

2016 - 2017: 2nd worst in GA
2017 - 2018 7th BEST in GA

How does a team with nearly the same players go for such a wide swing in results? The difference appears to be all in the system the coach uses. For example, how does a D go from a really poor defensive team where they looked poor, and then in a new system look like a much better system?

Does anyone have data on high scoring chances against? I am curious to see if this data lines up with GA, or if it shows these teams with good defense but poor GA/SA as the better defensive teams? OR does it match what we see with GA?