Well, for starters, looking back all teams in every season from 2008 (because that's when NHL started putting out the necessary data to calculate underlying numbers) to now,
there isn't a single stat or performance metric that the 2011 Canucks are at the top of the list for.
They are 64th in Score-Adjusted CF% (5v5 Possession).
They are 88th in Score-Adjusted SF% (5v5 Shot differential).
The are 177th in SCF% (5v5 Scoring Chance differential).
They are 162nd in xGF% (Expected 5v5 goal differential.
http://www.corsica.hockey/blog/2016/03/03/shot-quality-and-expected-goals-part-i/This is a fairly new stat. You can ignore it if you like, but it's proven pretty damn good as far as quantifying quality of play)
They are 38th in 5v5 GF/Game.
They are 34th in 5v5 GA/Game.
They are 17th in 5v5 GF% (5v5 goal differential)
They are 21st in OA GF/Game (Goals for per game, including special-teams)
They are 9th in OA GA/Game (Goals against per game, including special-teams)
They are 4th in OA GF% (Goal differential including special teams)
All numbers/rankings are for the regular season and taken from Corsica.hockey, cause I don't want to include shootout goals. NHLs numbers will be different, rankings will be close to the same with a few deviations, though not including shootouts actually helps VAN2011 a bit.
All rankings out of 300 teams.
Now, the next argument might be 'ok, maybe they weren't absolutely tops in any category, but they were just great at almost everything'. And that is a better argument. But even by that measure, they're not the best team. Because there are quite a few teams that are better in more categories at once. For brevity's sake, let's just keep it to cup winners.
Better than VAN2011 in Score-Adjusted CF%
DET2008 (Rank 1)
LAK2014 (Rank 3)
CHI2010 (Rank 4)
LAK2012 (Rank 16)
CHI2013 (Rank 23)
CHI2015 (Rank 30)
PIT2016 (Rank 49)
Better than VAN2011 in Score-Adjusted SF%
DET2008 (Rank 1)
CHI2010 (Rank 2)
LAK2014 (Rank 4)
CHI2013 (Rank 12)
LAK2012 (Rank 24)
PIT2016 (Rank 35)
CHI2015 (Rank 59)
Better than VAN2011 in 5v5 SCF%
PIT2016 (Rank 6)
CHI2010 (Rank 16)
DET2008 (Rank 24)
LAK2014 (Rank 27)
LAK2012 (Rank 43)
CHI2013 (Rank 92)
PIT2009 (Rank 127)
CHI2015 (Rank 176)
Better than VAN2011 in 5v5 xGF%
DET2008 (Rank 3)
CHI2010 (Rank 7)
PIT2016 (Rank 9)
LAK2014 (RanK 14)
CHI2013 (Rank 45)
LAK2012 (RANK 54)
PIT2009 (Rank 124)
CHI2015 (Rank 139)
Better than VAN2011 in 5v5 GF/G
CHI2013 (Rank 8)
CHI2010 (Rank 13)
PIT2009 (Rank 17)
BOS2011 (Rank 27)
Better than VAN2011 in 5v5 GA/G
LAK2014 (Rank 2)
DET2008 (Rank 7)
CHI2013 (Rank 8)
LAK2012 (Rank 15)
BOS2011 (Rank 16)
CHI2015 (Rank 30)
Better than VAN2011 in 5v5 GF%
CHI2013 (Rank 3)
BOS2011 (Rank 7)
DET2008 (Rank 8)
Better than VAN2011 in All Situations GF/G
CHI2010 (Rank 13)
Better than VAN2011 in All Situations GA/G
CHI2013 (Rank 2)
LAK2014 (Rank 3)
LAK 2012 (Rank 4)
DET 2008 (Rank 8)
Better than VAN2011 in All Situations GF%
CHI2013 (Rank 1)
Now, I'm not going to argue over which of these measures means most or least. I have my opinion, you can come to your own conclusions. However, the arguement that VAN2011 was the best team because they were the best over the most measures doesn't hold. Just among cup winners alone. And again, there were several teams that were better in a ton of areas that didn't win a cup.
It's unfortunate that Vancouver lost in the final to a worse team by many regards. And they were certainly one of, if not the best team in 2011. But from a historical view, looking back at the bulk of the cap era, they don't stand up as one of the best, let alone THE best regular season performance.