I'm not Aaron, but I have the Hanwag Alaskans and have also used mountaineering boots. The Hanwags can be more accurately defined as "mountain hunting" boots. i.e. built sturdier than an average hiking boot. However, they are in no way a "Mountaineering" boot. Although they have full length shank built into the midsole, it is nylon and relatively flexible. That makes it easier to walk on normal terrain by allowing your foot to bend in a more natural fashion. The drawback is that when you are climbing very steep ground or sidehilling, the boot will flex down slope every time you take a toe hold.
Defining a "mountaineering" boot is a bit tough, but generally they will have a very stiff full shank combined with a highly supportive upper. When you toe into a slope, you can climb it more like a ladder. As Aaron mentioned in his post earlier in this thread, it's just more efficient on nasty slopes and long scree slides. In fact many Alaskan sheep hunters use full plastic mountaineering boots with nearly no flex for this reason. The DRAWBACK of a super stiff boot is that it's clunkier to walk on more moderate terrain. They also tend to be heavier.
Yk
Yellowknife, I do believe you pretty much nailed it. One other thing I would add, is that, IMO, the shank/sole design is a lot better, more ergonomic, on many of the newer mountaineering boots for use on flatter ground. I don't hate my Hanwag Omegas on flat ground anywhere near as much as my old Technicas and Zamberlains. I had a real love/hate relationship with all of my older mountaineering boots, hate 'em at the trailhead, love 'em in the highcountry...