If you ride a touring bike like you would ride a racing road or mtb bike, with out of the saddle climbs, things like that, STI or Brifter shifting would be an advantage as you don't need to move your hands from the points of control. I have had several instances where I almost crashed because I was downshifting on bar end shifters while climbing really steep grades (15% or so) where I was doing all I could just to keep the cranks turning over.
However, for an application like actual bike touring, especially in remote areas, I opt for bar end or even downtube non indexed shifters simply for the reliability factor and the fact that things like cable stretch can be accounted for without having to rely on barrel adjusters.