Slaninar makes excellent points about the small-small combo. It also can cause the chain to bounce on and chip that pretty right chainstay. You can't change the chainline in front or rear without making the alignment in the large-large combo worse, and I doubt a 1 mm diff is going to resolve the issue anyway. Finally, the times when a rider will get down to the small-small and then not shift to the large chainwheel will be minimal, and as there is overlap between the two ranges there's likely a combo on the large ring that is close in ratio to the small-small. If one is going to shift to the large chainwheel anyway there is no savings in waiting until the small cog to do so.