Frame material gets a lot of press, but it's just one part of the overall design process. I think the one place titanium has the edge is corrosion (or rust). On a single tour of 1-6 months, that's not going to make a difference. If you live by the sea and the bike is exposed to salt spray, or keep your bike outside in the rain for years at a time, that's when titanium wins.
If you're touring with a load, you're going to want a frame that doesn't flex or you'll get shimmy. There may be a narrow point (e.g., rider plus load = 247 pounds) where a frame feels like it has just a little flex but doesn't shimmy. Add 5 pounds of food and that bike may start to shimmy on a long, steep downhill, or take 25 pounds off and it feels like a solid block of metal. Far better to depend on larger tires at slightly lower pressure to soak up road shock (although nothing short of full suspension is going to make the expansion joints in eastern Colorado less than miserable).
I'm thinking about N+1, and my focus is going to be getting a custom bike built by someone who knows how to balance material, expected uses, rider weight, and possible touring load. For the same money I might get a production titanium bike, built like a cookie cutter, and hope it works for me. Either is a valid choice. But I expect the custom will have a higher probability that I'll be riding and enjoying it in 10-15 years.