Awesome female ruler would be legendary warrior queen Lakshmibai.
The problem is, she was from India and this 3000 year old civilisation in civ series is always in shadow of one man, Gandhi (who I think is greatly overrated and I don't like him as a historical person at all, but that's separate thread). That means no queens (there were more great Indian female rulers) and no Indian empires, and once again India will be incompetent pacifist pushover far from historical 'character' of this civilisation. Eh.
Anyway, other female rulers I'd like to see:
*Vietnam with Truong Sisters (national heroines of Vietnam, two rebellious sisters generals riding elephants - such dual leader would be also super unique!) or Lady Trieu (another national heroine of Vietnam, also rebel general fighting Chinese hegemony)
*Persia had surprisingly many female generals, leaders and heroines before rise of Islam (my favourite is Pantea Arteshbod, and not just because her name screams 'badass')
*Nzinga Mbande, queen of Kongo (well, to be exact, one of neighbors of Kingdom of Kongo) and famous brave opposition to the Portuguese colonial domination
*Ya Asanteewa of Ashanti Kingdom (which would be pretty worthy addition to civilisations roster)
*Amanishakheto of Nubia (next worthy civilisation btw)
*Nefertete or Hatshepsut of Egypt (Cleopatra is extremely overrated by history, also female rulers of Egypt would be more interesting than Ramesses again)
*Roxolana as Ottoman leader would be controversial as hell as she was adviser and second in rule, not actual ruler, but I would be okay with it because she was very cool and she'd be much more interesting than Suleiman who always rules every ottoman/turkish civ in any civ game ever. Besides, civ already did such weird or much weirder choices for civ leaders (Theodora, consort, for Byzantium, semi-legendary Dido for Carthago instead of obvious Hannibal, and especially Maria 'ruled shortly and terribly' of Portugal who was very visible chosen just because BNW add-on 'needed' at least one token woman ruler) so...
*Joanna d'Arc would be controversial as French ruler too, as she never ruler the country, but I'd gladly welcome her - one of my favourite historical leaders, very unique person and pretty significant one. She'd be much more interesting than Napoleon who we will probably get (so France will end up as militaristic civilisation anyway).
Also, maybe her military operations were far smaller than Napoleon's campaigns, but in the end she succeeded in restoring French morale and them winning terrible war, while in the end Napoleon completely ruined France and brought its rivals to power over Europe

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Other than that, I'd gladly welcome old friends:
*Elisabeth of England (alternatively, Victoria would be cool too)
*Catherine of Russia (my favourite civ5 AI leader and personality, very distinctive person)
*Isabel of Spain
*Wu Zetian of China
*Theodora of Byzantium
Not Dido and Boudicca because while they were interesting personalities, they were a bit too... ahistorical to serve as great leaders examples after all (Dido - mythology, Boudicca - spontaneous rebellion ended in a devastating defeat). Maria of Portugal was bad case too.