I'd absolutely love more historical packs. I had Sims Medieval and enjoyed it though I did not play it enough for various reasons. In other gaming variations, I have often played historic strategy games or themes.
In order to play a historic theme, I need it to be completely immersive. That would be a completely separate save and I'd probably remove all of the pre-mades. I know that a lot of other people have done that. I'd need enough historic content to not get bored.
I've just been playing a modern theme to keep it simple, but I love historic content from different periods in history. I just wouldn't want a mish-mash of eras in the same save.