As far as I am concerned, the BBoAH should really only contain information about hardware built specifically for the original Amiga machines. So, while info about a particular PCI expansion bus is useful, I don't feel there's any value in including information about generic PCI cards you'd put in there. Possible exceptions to that rule being perhaps lists of known compatible devices.
Regarding "NG", it's a bit muddier. Nobody can seriously claim that OS4, MorphOS and AROS aren't anything to do with the Amiga (though many try),
For me it's not that these three OS's have nothing to do with the Amiga but that the hardware they run on (With the exception of those machines with Phase5 accelerators and AROS 68k builds) are not Amigas, therefore said hardware doesn't belong on a site that is supposed to be documenting Amiga specific hardware.
so in my view it's fair to include information about hardware purpose-built to run these operating systems. So stuff like the A1, Pegasos, Efika, Sam and so forth are all valid entries.
I'm not convinced, should Amiga DE devices like the Sharp Zaurus be included too? DE was the official succesor OS to the 68k Amiga OS at one point afterall, just as official if not moreso than OS4, despite it having nothing in common with the 68k OS nor even running on any 68k hardware.
Of course, generic PC's and PPC based macs are as much commodity hardware as anything else, so I don't feel there's a need to include them because as with vanilla PCI cards, it's all already out there. However, it would certainly be useful to include information about, for example, which specific models are supported. If you want a fully supported MorphOS, AROS or Amithlon box, it would be an ideal resource to check.
Isn't that easily available from amigaos.net or morphos-team.net etc already?
In the end it's up to the site owner what content he puts on it. Those of us who believe Amigas were only ever manufactured by CBM and Escom will never be convinced otherwise and vice-versa.