The customer base for touring bikes is very diverse about their wants. Some are willing to pay big bucks for the best and others will get by on cheap equipment. Most everyone has different priorities about what's necessary on a touring rig.
I believe a successful design should be flexible. That's why the LHT frame proved so popular. Everyone could build it up the way they wanted. It would be even more successful had they provided the option of 26" wheel sizes on the larger frames.
I'd like to see bikes sold with a lot of options as far as gearing, wheels, shifters, etc. so that people who don't necessarily like to swap parts on their own can get what amounts to a 'custom' setup. Customer A orders the 56cm frame with 40 spoke wheels, low gearing and barends for loaded touring while customer B can get the same bike with 32 spokes wheels, road bike gearing and brifters for credit card tours. You can do this already if you have a good LBS but it usually costs extra and is a pita. I'd like to see it as a simple 'check the boxes while ordering' type of thing.
I generally agree with most of this. The idea of being able to "check the boxes while ordering" appeals to me.
The one thing that I doubt is the assertion that the LHT would sell better if it had 26" wheels in all frame sizes. I am pretty sure that offering it only in 26" would be risky at best. Offering it as an option is almost like coming out with another whole bike. So yes they would sell some with 26" wheels in the larger sizes, but enough additional sales to warrant stocking two different frames in most of their sizes? I think that is far from a sure thing.
Some disagree, but I think the advantages/disadvantages between 700c and 26" are kind of a wash for most uses and to depart from the norm the advantage should be clear cut. Third world expedition style touring is the only place where there is a major advantage for 26" in any but the smaller sizes IMO.