Custom Classes in Halo 4?

So I was listening to the GI interview for Halo 4 yesterday, and I heard them discussing what sounded like custom classes for Halo 4. Could someone explain this to me a little more?

You get to change things like your primary, secondary, gernade, AA, and modifications, which you unlock with spartan points.

> You get to change things like your primary, secondary, gernade, AA, and modifications, which you unlock with spartan points.

When you describe it like that, it just sounds bad.

> You get to change things like your primary, secondary, grenade, AA, and modifications, which you unlock with spartan points.

That’s better. No, still sounds bad.