I'd like mostly new civs with some new leaders, but heaven forbid we continue to balkanize Greece. Three Greek leaders is two more than we need and three more than I care about.
There are too many Native American cultures worth including to keep featuring the same ones every time, but if the Iroquois must return there is absolutely no reason to resort to legendary leaders when one could use someone like Thayendanegea (Joseph Brant).I like new (or returning) civs better, more diversity, but some alternate leaders would be nice.
Personally, I'd like to see Hiawatha and Shaka return with their civs, but even above that, I'd like to see Abraham Lincoln return for America. I'd love to see and hear him in the style of Civ 6.