The only thing that bugged me a little was the portrayal of Augustus. But hey, maybe it's accurate, who knows.
Curious what you didn't like about it? Was it the actor or the character?
I felt the character genuinely likeable which doesn't seem to contradict historical lore. However, as you say, who knows what he was really like.
I am honestly hard pressed to find anything about the series that I didn't like and you know me...
I suppose it had the feel of a theater performance(exaggerated personae) and I found myself embracing this aspect but I realize this is off-putting to some. Maybe this is what bothered you? Like, I'm sure the "real" Augustus wasn't exactly like the character in Claudius because it's been dramatized but maybe his "essence" is accurate.