Remember that apple R&D, that found that mousing was quicker than keyboarding (because its low cognitive load doesn't interrupt your train of thought - it just seems quicker because you have amnesia when immersed in working out the right keys... [not applicable to expert fingers])?

Perhaps touching the screen instead of acquiring the mouse would be quicker and even lower cognitive load. This wouldn't be for every interaction, but as an adjunct to the keyboard - as the mouse is.

Not sure if true though - my mouse is at the same elevation as the keyboard, whereas the screen requires raising a hand about a foot. The cognitive load is lower though - people often instinctively touch the screen (if they haven't been screen-trained), especially when looking at someone else's screen. Perhaps that's a key? Collaborative use: a mouse is per person, but several can look and touch a screen.