To design the ultimate touring group, I'd focus on the equipment that best minimizes common tour-delaying mechanicals:

Broken spokes - Buy or build yourself a wheelset that can carry your load without issue and that can repaired in the field. The Velo Orange rear hub looks to be a perfect, since the freehub body can be removed without tools, so you don't need to carry special cassette removal tools. Phil Woods and White Industries are also field serviceable. Double-butted spokes and rims with thicker brake tracks will help the wheel last longer.

Shifting issues - Nothing is more annoying than when your shifting isn't crisp and precise. That's why I use 9-speed downtube shifters. There's no cable housing to gunk up for the front derailleur and only a little bit for the rear derailleur. The left shifter is friction, so I can easily trim the front derailleur to prevent any rubbing noise, and the right shifter is indexed but can be switched to friction in a pinch. I will always be able to shift well. IMHO internal geared hubs, integrated shift levers, and bar end shifters are not great components. You will disagree, but that's why there is no ONE touring group