I do not think he glossed over the Irish. They control parts of Dyfed in the books and Aonghus's warriors are always this unseen threat. Also in north Wales I think Dinwarch is an Irish interloper putting pressure on Gwynedd.
My biggest criticism with the books was the how he portrayed the religious struggles in Britain between the Christians and old Brythonic beliefs. There is no evidence of the survival of Druids or old pagan beliefs in the sub-Roman Britain apart from what the Anglo-Saxons brought with them. It is just Cornwell projecting his own anit-Christian beliefs into the era.
The Irish are not really presented as any real threat to Britain though, they are just a local issue really for Powys and Siluria/Gwent, and then not one of invasion, but off cross border raids, carrying away crops and slaves. The South of what until the 90's was the artificial County of Dyfed was of course an Irish ruled kingdom for quite a while, hence there are various placenames reflecting variations of Brigid/Brigida down in Pembs/Carms.
I suppose though, in fairness to Bernard, the plot is all very much focused on southern/South West Britannia, apart from a character from Rheged, but the reality was not just Germanic barbarians crossing the "German Sea" and hitting the British kingdoms from the East, but of Irish Barbarians crossing the "Celtic Sea" and taking what in Welsh, especially iirc medieval documents is referred to as "Yr Hen Ogledd" (the Old North)
I see what your getting at with the anti Christian stuff - it can be a bit of a bugbear with Welsh Nationalists of Faith - as apparently, to go by the Vatican's official line, though it has perhaps changed, there was practically no Christianity in Britain until the Venerable Bede and his ilk, because the Celtic Church was a bit more liberal, and of course, "infested/infected" with the Pelagian Heresy, so tends to be glossed over - though some Scholars are starting to revise opinions about Pelagius himself, saying he may actually have been far more "orthodox" or vanilla Christian than we are led to believe.
One thing I find odd is that Diwrnach, in name is presumably based on the myths of the Irish Giant, Diwrnach Wyddel, and to my Welsh ears, that name looks and sounds far more Welsh/Brythonic than Gaelic, though I imagine there will be cross over names between the 2 cultures.
Gwynedd doesn't exist in any shape or form in the Chronicles, which makes the timing seem a little dodgy, given that as he is writing down the story of Arthur, he is in a Monastery in "Wales" Gwynedd was founded by Cunedda ap Edern (AKA Cunedda Wledig) and according to the mix of myth, history, pseudo history and the poetry of Taliesin, that generally surrounds the "dark ages" Cunedda was a Prince of Manau Gododdin, a British Kingdom in what is now South East Scotland (I think Caer Edyn - Edinburgh was its capital) and supposedly at the request of the Romans, he and a large number of his people moved into what is now North Wales to protect the region from Irish raids and Piracy. The stories say that when Cunedda died, as was tradition, his lands were split between his 2 sons, Meirion and Ceredig, who gave their names to the regions, thus giving us the old Kingdoms and Modern County's of Ceredigion (my home & birthplace) and Meirionnydd, which is Southern Gwynedd - though I am not sure whether Meirionnydd is an outright County Council, or some form of Parish Council - after I think the infamous local authority region reforms of 1974, the one that caused outrage in Yorkshire by separating the ancient East Riding and renaming it Humberside, and massive outrage in West Wales, by amalgamating Cardiganshire, Carmarthenshire & Pembrokeshire into "Dyfed" and Gwynedd became somewhere between 2-4 different local authority regions, a few years ago, after local elections the very first Act of the new Council was to immediately rename the Authority region "Gwynedd" once more.
So, going by the general period that Warlord Chronicles seems to be set, there *should* be a Kingdom of Gwynedd, even if in fledgling status. The movement of Cunedda and a large amount of his people does appear to be historical fact, and the recent "shock" results of a DNA test, aparantly shocked everyone except anyone who had even the vaguest idea about the stories etc of Cunedda - the results showed a marked difference between North and South Wales - that whilst there was absolutely a "Welsh Gene" it was split into 2 related but differing types, which would make sense in the context of Cunedda, its been either known or suspected for a long time that there was not 1 "British" ethnic group, but several perhaps more peoples, united by a shared culture and language, much as there was not a single "English" ethnicity, but multi peoples, Saxons, Jutes, Angles, Normans etc eventually united under a shared culture & language.
I cant remember how Powys fits into the DNA map, whether its split between North & South Genes, or is one or the other, but Ceredigion, to the upset of a few people I know
has the "Gog" Gene. (Gog is slang for a North Walian, literally from Gogledd-North) when I gave the good news to a friend who isn't keen on Gogs for some reason, she looked at me and in all seriousness said "But I don't live in a cave!"
My paternal family are all Gogs, and half my maternal are from Gogland, and its borders, so I have always known that I carry the Gog gene
Mind you, I lost a lot of faith in the results in that shock test when I saw a bit more about the mechanics behind it - specifically, they are making these massive, for some ground shaking results regarding the peoples of Britain, for example, claiming that West Yorkshire has some sort of unknown Gene they have never seen before, and not found anywhere else - which sounded very odd even when I first heard it, as people DO move from West Yorkshire to other places, such as "That London" and other parts of "Southern Jessie Land" and it turns out, that for the whole of the Home Nations, a place of 66 million people, and even considering they were only testing white people, in a handful of areas, who had to pass very stringent qualifying criteria, such as iirc their paternal grandparents had to both be born in the area the applicant being tested was from and so on, that must still leave a pool of many multiple million people, 20 million plus, at least, and to make the claims regarding the genes/ethnicity of those 20 million plus, or however many they only tested
2000 people.
One of their claims is that the people of Abergele I think it was show a strong eastern Med presence in their genes, which would make sense, as it was a Roman mining settlement, but by my calculations, they cant have tested more than 3 or 4 people from there!!!
I can understand that Statistics can be used to plan things like Healthcare provision, or the Emergency Services, but not so sure you can do the same with Genes. If an area is extremely poor, then stats will tell you that, health wise, there will be lots of health issues related to alcohol, tobacco, illegal drug dependency and poor diet, but just because you happen to find 2 people with "Roman blood" doesn't mean the rest of the town will have it!
