I perfectly understand that a staff is harder to use, and has twice the amount of blades. But like you said, it's too easy to use in the game. Same thing for Jedi Academy. Since they have to keep the feats system, make it so that there are heavy penalties to use a staff. That way, it could be comparable.
Yes, the staff has more range, and the duals can strike more often, but the staff is a dangerous weapon for the wielder, and 2 sabers are hard on the balance. We saw this when anakin couldn't keep up with Dooku. In the game, however, they're exaclty like singles, except you hit more often.
I'm not saying Lucas created double bladed weaponry for the prequel, I'm saying he created the lightsaber staff for the prequels. That way, the fight would look more "epic". Well, I think (and I'm sure some people agree with me) that the Ep 1 duel is the worst. It's so artificial; there's absolutely no interaction.
The fact that an EU character once used a staff doesn't justify the fact that it's now in every "lightsaber" game. It all comes down to TPM.
Even though I would prefer a world of single blades, I understand the need of "cooler" stuff for games. I don't mind having staves in the game (especially since there's no MP, so I can just live in my own world (like my Ranger in NWN would get slaughtered by a lower level fighter with dev crits). In KotOR at least, my single saber guardian can live in peace without having to fight overpowered enemies), but I do think that some heavy tweaking is necessary. All the saber styles should be equal.