2. Either Mongolian leader, since it forces you to play one specific way, basically.
Every early unit you can build except chariots and archers gets a considerable buff...and both leaders have a REX trait. You're not forced into one path at all, more like two: war with SOMETHING (any strategic resource will do) or lean heavily on peaceful expansion.
3. Mao. I've never really found that good of a way to play as Mao.
Also an expansion leader though he is somewhat weak. Great starting techs, above average UU, but still not super impressive. A lot more dynamic/consistent than toku though, or even sal (though camel archers are not terrible in a strategy that emphasizes mounted heavily, such is not always viable).
Honorable mention goes to the Celts, Tokugawa, and Yara.
Yara does not exist (in the english release anyway). Zara belongs in a TOP leader list, not bottom. Powerful expansion traits with a punishing UU that is scary on its own and upgrades into some of the deadliest rifles/infantry this side of redcoats (aka big usage window). Celts are pretty weak with questionable starting techs and very lackluster UU/UB typically, but probably above the likes of toku/sal. Along with native america, Celtia does gain easy access to the ever-annoying early superchokepillage GII archers.
Do I hear Brennus mentioned as possible worst leader? Try playing at the higher difficulty levels, Brennus is clearly one of the best (though perhaps behind Gandhi and Lincoln)
What constitutes high? He has pretty good traits but awful starting techs...though CHA does not add to direct military power initially. Use for non-prat swords on high levels is pretty rare, once the AI gets a lot of axes or worse longbows it starts getting painful, hills or not. On certain scripts however a fast push for non-rifle gunpowder blitzes could be interesting.
Charlie's traits are better than toku's and he has better uniques (though the UUs are comparable).
Gilgamesh would be up there too, but trait synergy and UU likewise save him. And Gilgamesh is no AI you wish to be near in the early era, and creative/protective synergy is truly obnoxious when he is. The AI uses him well.
Super early courthouses and a painfully strong UU put him up. It's hard to rate a leader poorly when he's picked for high-level domination games.
Definitely not Stalin either. Stalin's traits are high-range medium, and he is by far the best leader for space race win.
AGG isn't terribly impressive, and IND is middle of the pack. Saying he's the best leader for a space win is so questionable it damages the credibility of the rest of the post. Strong UB aside, it comes late and any FIN leader, PHI leader that applies its early GPP well, or strong expander/early warmonger will post better results than stalin. You don't see him used for the best space win times in HoF, generally, nor do I see a lot of other top players picking him as a good techer.
Joao take some beating for crappiest leaders, and it is definitely between them.
The game's absolute best expander has no place at the bottom, even with a just-ok UU and terrible UB.