I think the voters will analyze pitchers the same way as they do now. The only change is the automatic induction for winning 300 games, which in some cases is awarding pitchers for longivity and consistency. You also have closers, and in the future, with the increase in the relief pitcher, HOF spots for relief pitching stats. The key ingredient voters use is dominance. Was a pitcher up for election one of the most dominant pitchers of a their era. You hear Peter Gammons and Tim Kurjkin talk about that all the time. Granted, certain stats must be met to qualify, but overall, the writers are in agreement who the pitchers are that will be locks becuase of dominance, and those who are close, and its the one's who are close that usually make up the most of the conversation during the time the voting process begins.
Subtracting the Steriod argument, writers and fans alike know who the locks as starters are from the recent past, Roger Clemans, Randy Johnson, Greg Maddux, Pedro Martinez with Tom Glavine not as dominant but his stats place him with this group.
Then you have the fringe guys like Curt Schilling(not dominant over his entire career), Mike Mussina (consistant and a top 10 pitcher in his era his entire career), and John Smoltz( wins/saves).
With closers its Trevor Hoffman and Mariano Rivera and everyone else.
This separation is like other generations where people like Steve Carlton, Tom Seaver and Nolan Ryan were dominant pitchers where Don Sutton and Phil Niekro were not.
If you want milestones that will get you inducted without question, winning 3 cy youngs awards or 4000 strikeouts or 500 saves.
Then there are combination stats that will also place you into the hall of fame.
200 wins and 150 saves (like John Smoltz), and vice versa( though 150 wins and 200 saves may be tested as Tom Gordan is very close to that)
250 wins, a cy young, 3000 strikeouts and a world series championship
150 wins with a sub 3.00 lifetime ERA.
winning 20 games 4x or more (going forward)
I am not putting 200 wins and 3000 strikeouts yet becuase not all pitchers who have those stats are inducted. I also believe if chances are greatly enhanced if you win 3+championships with a team.
If you wanted stats that will get you into the hall fame, only one matters, dominance, if you are, and your peers believe that, then you will be inshrined. Great examples of that are Sandy Koufax, Dizzy Dean and Don Drysdale.
Starting Pitchers like Johan Santana and Roy Halliday are examples of that today and Paplebon and K-Rod could become that as closers