I couldn't care less if Votto, Phillips and Bruce are righty, lefty or whatever. They are real good hitters or better and their handedness means little to me.
But when you have regular outfielders, starters, like Stubbs, Heisey, and Ludwick, you are dealing with more average MLB hitters.
If you are going with relatively average MLB hitters, then handedness becomes important.
If I'm going to have three positions 3B, LF, and CF with average MLB hitters, then I want a mixture of lefties and righties because I want the percentages on my side. If Rolen, Cairo, Heisey, Stubbs, and Ludwick are to perform like average MLB bats, then I'd rather have a mixture of "average" lefties and righties.
That's my philosophy, always has been. The real good hitters can be anything, I don't care. The guys who are average MLB hitters -- I'd prefer a good lefty righty balance.