I personally think touch screen could be too much a hassle in such situations. Button operated functions can be memorised and operated with your eye on finder, which is how most pros do it.
Couldn't agree more. ?Yes there are some functions that you may need to glance and use the menu. But having the ability to quickly change things on the fly without taking your eye away from the viewfinder is key - and your point there steps that up - for the bulk of us changing fstop, SS AF points, ISO on the fly is about getting that moment, you example is literally life or death!
With that said, if a touch screen could be in addition to all the normal buttons and the wheel, I guess thats fine ---- but - I would bet it would come at a cost (imagine this world, the mkiii has a touch screen, but its now list price of $3799 - because it has the new touch screen...
my 2 cents, keep that stuff in the lower model SLR's or P&S