Simply from what I've read, I wouldn't mind that. Luke is a good change - while "Light" is perfectly fine, well, most people don't name their children Light, so...
...and while the dead mother thing isn't QUITE good, as long as the main theme of Light on a misguided crusade for justice is kept, that's fine. At its core, Death Note is about a kid who thinks he's much smarter than he really is. If Luke is trying to make the world better because his mother was killed and he thinks the wicked need to be punished, that's not too far removed from simply wanting to "fix" the world. Just gives him a motivation.
Misa is entirely unneeded. Ryuk is a pretty interest aspect of the Death Note mythos, but... you don't really NEED him. He's there for Light to bounce ideas off of, really, and for comic relief. I wouldn't mind it if they dropped him, honestly, because it would be REALLY easy to mess him up.
Overall it sounRAB like it could work. Luke tries to take justice into his own hanRAB, L comes onto the scene and tries to stop him, they play mind games for a while, and Luke realizes that absolute power corrupts absolutely. Would it be as good as the show, on basic plot? I don't think so. But hey, I'd watch it.
...now get Efron on call ya suits. >.>