Good discussion all, thanks for the perspectives.
I think tubeless will eventually hold a lot of promise for touring. It's not there yet across the board for everyone (but great for some), but improving. It think it helps that the big tire manufacturers are now putting a good amount of resources/development into the roadie/racing tubeless market. That will likely lead to more improvements for both road and, by extension, road touring tubeless....mainly re standards and compatibility, and just better products.
For road touring, my benchmarks for going tubeless:
1. Tire/rim combo w/ hassle free installation, including seating the tire w/ regular pump. Not interested in tire/rim combos that require a compressor to seat. I know of anecdotes that go both ways...seat tire w/ compressor and all is good going forward, seat tire w/ compressor and constant trips to bike shop to reseat. Blah. For touring it's gotta be easy install/reinstall.
2. Tubeless rim that is not outwardly hostile to installing a tube in case of severe sidewall damage. Some first hand anecdotal experience w/ this on 29er rims. It can be a bear to put tubes on certain tubeless rims out there. You might never have to do it, but if you do it will already be a less than fabulous situation. Why fight it. There are already plenty of tubeless rims out there that work fine w/ tubes.
3. Good variety of sealants that are appropriate for wider variety of pressures, etc. Not all lower pressure mtb stuff. This has already improved quite a bit, but can add to the learning curve for some folks who don't want to spend time geeking out on reading bike product review sites!
I do plan on trying out road tubeless for the first time this year. I am fortunate to have 2 wheelsets for my roadie, one fully tubeless ready. The other traditional clincher/tube. So if that trial run goes well, I expect I will transition the touring bike to tubeless for 2022. My rims are already good to go on that front.
C