I'm not worried about that part. But I have a holy crusade. I dislike waste. I dislike over-engineering. I think small is beautiful, and the guildeline should always be that performance and size are more important than features.
Every device needs a unique number.
I don't think you do. But that's how ludicrous a 64-bit device number is. In fact, a lot of the reason for the dearthness of major numbers is the fact that we use multiple majors for some stuff that really wants many minors. So 8 bits for major is actually fairly close to perfectly livable - or at least would be if we had more minors. Which means that 32 bits of major numbers is ridiculous.