Regarding your thoughts on the demise of RBI... yes, RBI is a useful stat because it tells us how many runners a hitter drove in-- a very desireable commodity for a middle of the rotation hitter. But it has flaws and faults.
1. It is a 'counting' stat, meaning it's not a rate. So a guy who drives in 110 runs in 650 at-bats may seem better than someone who drove in 105 runs in 550 at-bats, which isn't true.
2. A lot of it depends on oppurtunity. It's hard to drive in baserunners when there are none! But that is obvious.
3. Also, you can get RBI for some weird things.... like if there is a runner on third, the pitcher throws a wild pitch... he scores. RBI for you, even though you didn't do anything. Little things like this make it less accurate.
However, I think there are other ways to measure RBI quantities that you don't need a degree in statistics to calculate. One of my favorites is RBI percentage. It tells you what percentage of available runs you drove in. If you hit a home run in every at-bat, thats the total number of potential RBI you have. MLB leaders in RBI percentage last year:
Jason Giambi (137/869/15.8%)
Manny Ramirez (122/779/15.7%)
Frank Thomas (143/968/14.8%)
Todd Helton (147/1000/14.7%)
Edgar Martinez (145/1005/14.4%)
By the way... the MLB average RBI percentage is 8.5%.The Rox Reference Fans Network(http://www.expage.com/roxreference)