"... what is it about the A1 board that makes it so special when there are tons of other board designs out there that were already superior ... "
That's true for x86.
But for PPC, there was only Apple and that was not an option. ArtisiaS is the only northbridge outside Apple for PPC that has AGP2x.
TeronCX mb was available in some form, it just needed finetuning before it started to be in sellable form for Joe Average... Now there exist also the Pegaos mb (which is a more polished mb), but so far it is unlikely that we see AmigaOS4 for that.
The most important thing is to get the legacy HW independant AmigaOS ready, FOR ANY HW.
