I'll back you up 100% on that! I have a pair of Scarpa Escape, semi moutainering boots that have a stiff sole and gortex liner. Price is much better than motocycle boots and they are more versatile. These hiking boots have better tread than bike boots and more comfortable. The stiff sole are great for standing up on pegs. When it's realy wet, i use gaiters, they go up to the knees and no water will go in your boots,and helps keep the cold out. I'm like you, I like to be able to get off the bike and go explore on foot.No need to have another pair of shoes.
I realise that a motocycle boot will protect you more from a the bike crushing your leg but with the r1200 gs, the engine heads will hit first, and if you have your paniers on, that's even more protection.
I enjoy backpacking and hiking also, this way i have extremely good pair of boots that are vesatile for the things I love to do!