I think that’s true in most popular genres, like thrillers. Most historical fiction is better written but Celtic = appeals to wiccan/pagan types = less demanding readers. It’s like how the generic romantic fiction or Christian fiction novel are horribly written, while the generic science fiction novel has better mechanics.
Sigh. Trust me to fall in love with a genre that demands more than ‘just’ a story...
I was going to suggest you try writing in some other genre for a change... but now the idea of you trying to write a ‘bodice ripper’ is going to amuse me the rest of the day.