My Preference would be merely to balance positive traits, but I'll think about it.
I'm kicking around an idea of adding 1 leader to each civ (Mali would become part of Songhai and I'd add Poland-Lithuania as the 40th) because I believe I have the artwork to do it (I'm pretty picky about Leaders, I hate it when they look like clones of another leader, like "oh look, it's napoleon with a mustache!). The question is gameplay, I'd have to whittle each civ to 2 Unique Civ abilities and then create 10 leader traits with 8 leaders each having that trait, and each civ having access to two leaders with different traits.
So for example if I'm the Inca, I start with a source of stone and have a bonus to reasearch as my civ UA. I can either play as Huayna Capac, who is a financial leader, and gains extra gold from plots with 2 gold, or as Pachacuti, who is a cultured leader, who gives 3 culture per turn per city. Ideas for traits are Cultured, Maritime, Militaristic, Financial, Strategic, Protective, Spiritual, Expansive, Charismatic, Commercial.
This would be in addition to adding 7 guilds and several heroes. Guilds are corporations that come early. The first, the Knights of Santiago, is founded by a Great Prophet and let's you train Knights of Santiago, very strong versions of Knights. This guild conflicts with the Assassin's guild, which is founded by a Great Spy and let's you train more effective spies. Etc.
Last but not least, Asaf has promised the next iteration will have Better BTS AI merged in, for a more competitive experience, and I may ping him and ask if he'll also do the DLL for Orion's Inquisition Mod, so you can train Inquisitors and go for Religious Victory.
Oh, and Russia's changes aren't released yet, I've been improving the mod in my free time. Russia will play UP in your game.