Question about triples...

[The Loveable Losers]

Yeah, let's not start messing with the existing stats like slugging percentage.

That said I see where you're going here. I think what you're wanting though is something that is a bit more complex than just valuing doubles one way and triples another. What you'd want to look at is some batted ball data that's just now starting to be collected. Information like where the ball is hit, what angle, what velocity, what direction, etc. That information is actually being collected sporadically at this point and should be very useful to study the type of information you're wanting to study - specifically what how hard and how well each player hits the baseball.