> Especially when AFAIK you need to use a rather large toolchain to access the obtusely indirect APIs.
Weight that (literally only a couple macros) versus the idea of having to dig out a 16-bit toolchain and/or a DOS extender which also brings its own obtusely indirect APIs with it. In case you decide to do the former, you'll probably have to rewrite big chunks of your program in order to rearchitect it around XMS. In case you decide to do the latter, you'll be able to use a 32-bit toolchain, but you'll have to write your own drivers for high-resolution graphics, sound, and depending on your luck, mouse. All of this UEFI brings for free, and even for recent hardware.
Weight that (literally only a couple macros) versus the idea of having to dig out a 16-bit toolchain and/or a DOS extender which also brings its own obtusely indirect APIs with it. In case you decide to do the former, you'll probably have to rewrite big chunks of your program in order to rearchitect it around XMS. In case you decide to do the latter, you'll be able to use a 32-bit toolchain, but you'll have to write your own drivers for high-resolution graphics, sound, and depending on your luck, mouse. All of this UEFI brings for free, and even for recent hardware.