Best Scoring Stats for 6 x 6 Roto League

[dirtdog123]

Our 3rd Year 6 x 6 Roto Keeper League uses the following stats:

Hitting:
AVG, OBP, RBI, Runs, SB, HR

Pitching:
W, S, Hold, SO, ERA, WHIP

Currently we are debating dropping either OPB or AVG and adding either SLG or OPS. I see the strongest arguments as supporting dropping AVG and using OBP, SLG, RBI, Runs, SB, HR.

I believe that our current system overvalues the base hit and undervalues the extra base hit. Thoughts? Any compelling evidence or arguments I can pass on to league members will be appreciated.