So, in summary, the answer is as simple as which kind of bike is best ,and it is completely dependent on several factors including terrain, duration, your style of touring/camping (ultra light or well equipped) and what you intend to do on your trip(is the touring the actual trip or is it camping with mtbing along the way?). So there is no "best."
I've gone with a Yak but only because I am not intending on long paved touring ,rather a rail grade trail with stealth camping and some off roading all via a 29er hardtail.
I think if I were serious about touring on roads for long distances involving a road or touring bike(which I don't have) I would choose panniers.
Actually, I am liking the latest trend in off road touring with frame baggage. These systems do encourage minimalism but make for a much better handling bike. In a way this system is appealing as it takes more advantage of the ultimate in weight savings, bushcraft skill. One could get away with just a sylnylon tarp and a knife and make good shelters. Perhaps even manage to catch your own food although this would likely take too much time and energy away from a trip but still,,,