Guys come to High Fives league next season and I will show you how much PC effects a game. All season long I took ridicule for being lucky. My starting pitchers are rated 72-69-75-72-73 OVR and I won 109 games with them. I play in a hitter's park and was 2nd or 3rd in the league in ERA as well. I'm not saying it's the only way to build a team but I will tell you it works for me. My theory is that for cetain pitchers it matters more. Like the guy I linked to earlier. He has two good pitches (90/81) and three poor pitches. So if a catcher calls for his good pitches more it makes him a better pitcher. Just makes sense. And yes, I do realize that individual pitches aren't called in this game. But if it effects the success ratio and you are drawing more from two pitches averaging 85 than from three pitches averaging 40, well that's my point.
Here's the other thing... Staff maintenance. More good innings out of one or two pitchers can make a huge difference on things like bullpen fatigue throughout a season. I was able to go half a season with only ten pitchers and never saw a reliever enter the game tired (less than 90%). The first half of the season I used 11 and realized I didn't need that many.
To each his own but high PCs work for me. Do other ways work as well? Sure.