Most of these are all just implementation or platform divergence issues, though what was the FPU emulator issue? That actually seems fundamental to formatted output strategies.
Well, regarding the emulation issue, you've got me there, slightly, because that item was going by what I remember of what my teammate told me in the pub about 12 years ago :)
The platform was the Playstation2 and the issue was (as I recall) that the system's FPU supported floats but not doubles, and the supplied libc wasn't fully compatible with the compiler flag that effectively did a typedef float double. (I assume printf was affected because of the traditional varargs promotion rules.)
I suspect it was easier to write a new printf than figure out how to rebuild libc, assuming you were even allowed to link the final game to your own libc in the first place...
(As for the rest being simply differences between one platform and the next, that's quite true. (And you can usually work around to one degree or another - believe it or not I've worked on a number of multi-platform projects that didn't rewrite printf, though funnily enough every single one had to wrap it.) But then, for what reason does one do this sort of thing, except to remove these differences? You might as well rail against #define stricmp strcasecmp and the like - writing your own printf is just a difference of degree.)
