Lol, I thought I was the only one who was so critical about facial features. I did my procedures back in 2009-2011, so I had already done all of this research.
For a Korean, my face wasn't really all that flat, but still flatter compared with normal Caucasian faces. I had a very slight underbite (class 3 malocclusion) which wasn't really bothering me functionally, but was enough for insurance to step in and cover the maxillofacial surgery. They would only cover LeFort I, although a LeFort II would have been nice. LeFort III seems like it would just push your entire anterior portion of your face forward, so not really solving the "lack of projection" issue. If you're going for the Caucasion look, then you would need to project your midface via LeFort II, then probably push back your upper lip/premaxilla via LeFort I. So for the extremely flat severe case, you would probably need to do a combination of LeFort II anterior projection, and a LeFort I posterior retrusion, to emulate a Caucasian face which has a projected the midface, but flat and retruded upper lip area. Asians generally can have the opposite features where the midface is pushed back, yet the upper lip area projects out like a chimp with a prominent lower jaw. Also, Asian faces can tend to be long vertically. Although technically you can shrink the LeFort I area by removing part of the bone vertically to make the face shorter, the real issue lies in your soft tissues (skin). There's no way to really vertically reduce your soft tissues like you can with bone. So if you were to shorten that bone, you still would have a tall upper lip and when you smile, your visible teeth is in the wrong place now. No real easy fix, unfortunately. As far as facial definition goes, Asians tend to have thicker skin, so any underlying structure will not come through as easily as it does for Caucasians.
Also keep in mind that many doctors, especially those in the US, may not perform these LeFort procedures unless they deem it medically necessary, even if you're willing to pay out of pocket. The more advanced LeForts like the LeFort III may need access near your eyes and there are always risks that most rational doctors won't take on, even if the risks might be acceptable to you and me. It's a lengthy and committed process too, where you need to coordinate with your orthodontist to possibly get on braces and align your teeth perfectly. Post-operative care also requires you to have your mouth wired shut eating out of a straw for months for the bones to fully heal too.
I ended up doing a LeFort I rotation and reduction of the lower jaw to solve the bite problem. My face didn't have that stereotypical flat Asian face, so I don't think I really needed a LeFort II. A couple of years later, I had eyelid surgery done, followed by augmentation rhinoplasty with rib cartilage, enhancing both the entire bridge and the columella extension. I had a deviated septum, so we knocked two birds with one stone and insurance covered most of the procedure. The rhino had an added benefit of simulating an epicanthoplasty procedure from the raised bridge stretching the skin around the inner part of the eyes.
I'm now looking into possibly doing a forehead procedure. I have defined brow areas giving that deep-set eyes look, but looking to fill out the forehead area above them.
Just sharing some feedback and experience that might help some people here.