Louis XXIV
Le Roi Soleil
Carthage used elephants extensively, yes, but as you pointed out yourself, they were used by many differant peoples during that period. (Hellenistic-Classical era, whatever you want to call it.) I think something like Numidian Cavalry from Civ IV would be better. As far as seafaring goes, they did represent them well, with the Quin and free harbors, though I wasn't really refering to that aspect. And in my defense, I never explicitely "assigned" them to Hannibal, though I guess I did suggest so. Whoops.
I love Numidian cavalry, don't get me wrong. I advocated them since Civ3 (since they used Libyan Mercenaries and called them Numidian Mercenaries) and was thrilled when they were changed in Civ4. However, I think it's a mistake to say that Elephants weren't associated with Carthage. Sure, they weren't exclusively associated with Carthage but, then again, neither were Numidians. After all, they were used by Rome herself against Carthage. The Carthaginians idolized the use of Elephants in warfare, though, and used them extensively inside Africa. The coins produced by Hamilcar Barca and his son Hannibal used the Elephant motif. Elephants were important.
Now, in a perfect world, I'd love Numidians. But, given Civ5's features, I like the Forest Elephant. The reason is this: In Civ4, Numidians were erroneously shown stabbing with their javelin. Now as the name javelin should suggest, it's a ranged attack - they threw them. In Civ5, ranged attacks (pre-gunpowder) are represented by ranged units. And, this early in the game, it makes far more sense to have a ranged unit as a Chariot replacement than a Horseman replacement. And they already did that with the Hunnic Horse Archer. The Numidians likely weren't chosen because the overlap with the Horse Archer would have been too significant.