Yeah, I already addressed this but Darth kind of skipped over it.
But to re-state: I think the best comparison is Roger's 7-3 record in Wimbledon finals vs. Pete's 7-0. Two of Roger's final losses were at ages (32 and 33, in 2014 and 2015 respectively) that Pete was retired from the sport. Consider also that the last Wimbledon final Pete appeared in was 2000, at age 28. So to penalize Roger for losing in finals at age 32 and 33, when he was 4-5 years older than Pete was during his last final, doesn't really make sense.
Add in his final loss to Rafa in 2008, and you can swap that out for Pete's QF loss to Richard Krajicek in 1996. Is losing to a surging Rafa in a final worse than losing to a much lesser player in a quarterfinal?
Another variant of this argument is looking at Ivan Lendl, with his 8-11 Slam final record. Lendl is the only 6+ Slam winner of the Open Era with a losing record in Slam finals. But consider two things:
1) Lendl appeared in 19 Slam finals. The only players in the Open Era to appear in more are Roger (28), Rafa (22), and Novak (21).
2) Lendl's prime years overlapped three separate generations of greats: Connors/Borg/McEnroe/Vilas in the late 70s to mid-80s; Wilander/Edberg/Becker in the mid-80s to early 90s, and Sampras/Agassi/Courier in the early 90s. I haven't done an in-depth study, but I'm pretty sure that of any great player in the Open Era, Lendl's prime years had the most "competitive density" - that is, he played in the hardest context of any great player of the Open Era.
I know we're not talking about Lendl, but I think it illustrates the point: that when we talk about greatness, we can't only look to the win column. We have to look at the other results as well. Another example of this is comparing Andy Murray and Stan Wawrinka. Andy is 3-8 in Slam finals, by far the worst percentage of any multi-Slam winner, while Stan is 3-1. How do we compare the two? Not to mention Andy's far superior results in other tournaments - 20 big titles vs. Stan's 4, etc.
All of these are variants on the theme. Looking only at Slam wins is just the surface and only tells us so much about how good a player is, historically speaking.