Three problems with your point here:
1) Your stats disregard 30 some percent of all scoring. It's a fairly common way of detracting from one of the best powerplay players and the greatest powerplay goal scorer of all time.
2) The Pens likely have the upper hand in terms of goal differential in the seasons you've not included. They certainly have it as a team as a whole.
3) Ovechkin is always going to have tougher match-ups than Crosby because the Capitals have generally never had a second line that would occupy anywhere near as much attention as Ovechkin's line. Whereas for the Pens, Crosby is typically going to split time against the opposition's top D pairing or shut down lines with Malkin.
You just made a post to suggest it's not wins and losses that matter, but goal differential at 5v5 only. But you rely on wins and losses here (which is a proxy for making the playoffs). Personally, I'm not a big believer in WOWY stats because there are too many other factors that amount to important context.
