Touring groupsets
[Recent thread was asking for a specific frame. But what about the bigger picture?]
I'd be interested in reading opinions wrt touring groupsets. I suppose that we all agree on a few basic ideas, such as a wide gear-inch range and the availability of a really low gear-inch. Yet things are changing quite fast, so... what about:
1. 1x drivetrains (personally not attracted to, because of the very large steps, but 1x are becoming more affordable and, from what I read, the new standard for MTB.) For instance, I read yesterday that 12-speed chains were of a much better quality than 10 and even 11 (twice as many kms before "stretching" more than 0.5%), which raises the spectre of future improvements focusing mostly on this standard. And if considering a 1x, is there any reason to prefer a derailleur system (Shimano or SRAM) vs a Rohloff? Anyone knows if it is possible to customise a 12-speed cassette (ex: instead of 10,12,14,16,18,21,24,28,32,36,42,50 -> 14,15,16,17,18,21,24,28,32,36,42,50)
2. My reference groupset was the Shimano trekking XT, on a frame with flat or butterfly handlebars. How convenient/practical is it to install these components on drop bars (I saw dual brake levers setups, what about shifters? Are brifters a real option? Any issue wrt to handlebar diameter?)
3. Will 3x10 become obsolete in the foreseeable future, to the point of repairs/spares becoming a challenge (as seems to be happening with 26" rims/tires)
Asking because I *may* build another touring bike (kids are growing up).