Intoxicatingly put. Very excited about those compromises. Gear materialism is my greatest sin.I have to admit, I like the challenge that a little bike poses on a big journey. I think a TW would make a fine Rocinante compared to the BMW Bucephalus that are more common. There is a great thread on ADVrider called the "minimalist touring thread" you may be interested in. A fairly stock TW, a backpack strapped to the seat and rack, and some way to extend the fuel range seems like a fine way to travel Mexico, Central America, and much of Northern South America. I would desire a bigger bike for Argentina, because it is flat and windy, not unlike Alberta or Saskatchewan, but that is all part of the compromise, isn't it?
Keep it about the trip, not the gear.