I will admit to being annoyed by the huge Sulla info dump. I won't encourage you to continue with the series if you did not like this novel but I will tell you that the info dump makes sense in the context of the series. Life's too short to spend time reading books you don't like.
If the information is necessary for the rest of the series, that's where the information should be. The author had done fairly well up to that point of sprinkling background information here and there. And yeah, I don't think I'll be continuing. The book sounded promising but most of the twists had at least occured to me even if I hadn't quite worked out how they fit together so purposefully leaving the reader in the dark when Gordianus had (maybe?) worked things out didn't really work for me.