I have not owned a Jotul, but had a Morso which has many similar design features. Today I have a Pacific Energy T5, a welded steel stove with cast iron cladding. Frankly, I think this concept is more durable, since the cast iron parts are way cooler on this stove and the steel plate firebox is welded tight and the parent material is ductile so much less chance of cracking.
I think the chimney length / draft issues that were raised are valid. I too have a 30'+ chimney, perfectly straight and all but 4' inside the house envelope. I made the mistake to not put in a second damper when I installed my stovepipe, the first is about 7" above the stove outlet. My stove is still marginal with the single damper. On really cold nights it can be difficult, even with the damper fully closed to prevent a runaway. Supposedly dampers are more effective if they are installed as high as you can get them above the stove, but my damper was retrofitted after the whole thing was installed.
So I have a theory for you: With your high draft, I suspect that you had a leak at one of the seams at the bottom of the stove and the extra air from that source cause a local overheating. That, over the entire season caused a crack. It does not sound like you have a dealer with a good stove mechanic. If you get the stove back with more leaks than they got it with, that is no doubt going to fail even faster than the original.
IF, you get the stove fixed properly and sealed up tight, then for sure put in Min 1 and I suggest 2 dampers as high as you can reach (you have to open them before opening the door), then your draft control issues will go away. If you notice any air leak, let the stove cool down and get some stove cement in there inside and outside to seal it up. Just follow the curing instructions. Don't allow any leak to persist in a cast iron stove, or it will warp or crack.
