So, are people using LDGs in favour of SLB? If this is the case, would it be beneficial to have support for this in the OS?
It's hard do say -- LDG seems to be preferred in France only ;), SLB is on the other hand really dead (last thing I saw as SLB was Draco's experimental GEMMA library). Personally, I'd go LDG way, if nothing else, you've got authors / developers here, in ML.
And the LDG + memory protection issue - why is this?
I think this isn't issue anymore (fixed by my last patch), at least in non-kernel mode (without ldg.prg) but I wouldn't be surprised if this works well, too.