They didn't play enough of Lelouch's voice to be sure, but the one line he did have gave me strong Death Note impressions. Since Lelouch is the naughty one for standing up against authority and the system I think they're giving him the more immature sounding voice so that people will not identify with him as a person of wisdom, just like they did with Light. I abhor this practice in dubbing more than anything else about it, but I'll probably still watch it on [as] just to see the story again.