As commented, not as interesting and entirely new leaders, but worth it if there is no other options. If this would help the AI to focus more in a type of victory, it might even be welcome. Extending (and fixing
)
@King William I list:
Pillars Cyrus focused on happiness and/loyalty
Patronage Nzinga focused on science
Stratego Pericles focused on military
Inquisitor (or Pious) Philip (focused in RV) vs Conquistador Philip (focused in Dom)
Civil (Builder) Trajan vs Centurion (Expander) Trajan
"Defender of the Faith" Saladin with military focus
...
Back on the days of Beyond Earth, I had an idea/suggestion which could apply as well the persona packs - in BE, firaxis told us they did not provide the leaders a very fleshed-out personality/strategy (versus, e.g. what you had in Alpha Centaury) because they wanted the playtroughs to be not equal to each other. I tought the principle was worth, but not the implementation, as it led to most playtroughs facing uninspiring leaders... but the same idea could be implemented by giving each leader three-four different personalities that evolve during the game.
In example you could have a "grandma" Elodie, peaceful, diplomatic, leaning towards purity affinity; an "elitist" Elodie, thinking herself better than anyone, quick to anger and maybe leaning more towards supremacy, or an "aesthete" Elodie, isolationist, mixed purity-harmony, and same for other leaders), and which were choosen randomly at the start of the game (or, if you want more complexity, where selected depending on the status of the civ at certain key points of the game). This way, even if you knew you were playing against a leader, you still had a lot of uncertainity regarding which version of the leader it will develop to.
Persona packs would give that away by changing the model of the leader early on (doh!) but still can provide you with different AI focus to play a civ, and that is the interesting thing. A civ does not need to be always your best neighbour or your "keep an eye on your border" neighbour, because you may face different personalities of their leader in each game. Nevertheless, let's wait and see how it works out with Teddy and CdM before providing a final opinion.