I find these guys to be incredibly helpful in deciphering the psychology of the hall of fame. They were nearly complete contempories of eachother. Glavine pitching from 1987-2008, Schilling a year off on both ends ('88-'07) and Mussina coming in a couple years after that ('91-'08). They are all Hall worthy pitchers based on their production but there is a big gap in how their cases are perceived. Glavine is almost a shoe-in to get in on his first ballot. Schilling looks to have to wait at least a couple more years. Mussina is almost a full-step behind Schilling and possibly in for a long Blyleven like crawl into the Hall. Why?
Glavine, who honestly might be the least productive of the three, gets in because he's the perfect checklist Hall of Famer. Did he win 300 games? Yes. Did he win Cy Youngs? Yes. Did he pitch well in the postseason? World Series MVP, bitches. All-Star? 10 times. When you come up with a list in your head of all the incidentals a Hall of Famer should have Glavine has them all. Add that to a production that was lengthy and worthy and it's a slam dunk.
Schilling and Mussina on the other hand fail at this first glance. 300 games? Mussina no, Schilling not even close. Cy Youngs? Nope.* All-Stars? Yes, but only 6 times for Schilling and 5 for Mussina. Hence the big gap between Glavine - who might get over 90% of the vote this year and Schilling (around 40% likely) and Mussina (around 30%).
Where Schilling differentiates is that he pitched great in post-season... Well he did and he didn't. First back to Mussina. He overall pitched much like Glavine did in the post-season, which is pretty much the same as he did in the regular season. But what Glavine did was have particularly good post-seasons. 1995 (the WS MVP year), '96, '98, '99 to mix in with some stinkers. Mussina didn't have any terrible postseasons, but had some blah ones and none that stand out. Which brings us back to Schilling. Schilling had two of the most standout postseasons we've seen. In 2001 he (and Randy Johnson) were unhittable. In 2004 he won the last two games he pitched in dramatic fashion. While the rest of his postseason work was hit or miss (did you remember he sported a 7.45 ERA for the 2004 post-season heading into the bloody sock game?) these moments carry a lot of weight.
What does this all mean? It means that when you ask someone to give their opinion, which is what you are doing by asking them to vote, perception is going to weigh very very heavily. Glavine is perceived to be the best of the three because of the milestones he reached and the accolades he garnered. Doesn't matter that he let a lot more guys get on base and score (relative to league). That's secondary to the picture formed in our heads by the things we notice. You see something similar with Schilling. Doesn't matter that he kind of alternated great and so-so in three out of four postseasons. That other one was dominant and his good performances in the other ones stood out. This matters. Think Jack Morris - great in 1984 for a dominant Tigers, gave perhaps the most memorable pitching performance in a WS in the last 40+ years in 1991. Doesn't matter he was terrible in 1992 or lost his only game in 1987. His success stuck.
When you ask people to vote this is what you are going to get. Three guys, all Hall Worthy, all in the same ballpark of worth, going in at three different times, possibly backwards in deserving, because of perception. It's a bit crazy, but if you didn't want this you'd just draw a rough WAR line in the sand. Everyone over X in. Everyone under Y out. The few between X and Y or the very very random special case? Those get debated.
But who wants this? We already know who is over X and under Y. I basically know the objective best and how guys roughly compare to eachother. I don't need plaques in a building to tell me that. What I don't know is what everyone is thinking. So vote. It's fun to see perception play out.
*For the sake of argument I went back and looked at all three pitchers years where they got Cy Young votes. Glavine was never "robbed". Schill wasn't either but that was poor timing, being fantastic behind monster years from Randy Johnson, Pedro, and Johan Santana. Mussina was once when by fluke of run support Clemens went 20-3. 20-3! Perception!