I assume you've read all the Niccolo ones as well as the Lymonds?
I read all the Lymonds when I was 18, and still reread them each year and find something new (I am now 43), so they are compelling. I was so sad when I read that DD had died.
Sharon Penman is very good, if not as complex, and I quite like the huge books by Margaret George - the one about Henry VIII by his fool Will Somers was good.
I enjoy the Outlander series by Diana Gabaldon, and the Shardlake books aren't bad either.
tbh, I don't think apart from Umberto Eco's Name of the Rose, there has been much to equal DD in that genre. I am always on the look out as well. Perhaps PD James could turn her attention to historical novels instead of crime for a bit?
The newest Penman makes sense if you have read the other two in the trilogy. What put it all into context for me was reading The Greatest Knight by Elizabeth Chadwick, which is one of two books about William Marshal. It's much simpler, but effectively gives a straight narrative which helps if you then read the latest Penman.
I did buy the books accompanying the Lymond chronicles which I found fascinating. They help to explain things in the books, though I sill can't figure out if Kuzum was Gabriel's and Joleta's, or Lymond and Oonagh's.