So, with 64-bit machines we have access to a larger address space than we'll ever need (64k should be enough etc.) and only a tiny fraction of that is mapped to anything sensible on my machine at least. Why not make addresses denser than 8-bits then?
We should have addressable bits! Of course, reading bytes or words would still have to be aligned. I belive this is the next great step in computing.
Or do like Java does and use 32-bit pointers to address up to 32GB of memory, as objects are guaranteed to be 8-byte aligned there.
Really, the whole 64-bit thing has gone out of hand. The processors support just 48 bits, some OSes further clamp that to 232 pages (44 bits total), and in either case it's a tremendous waste in the vast majority of the cases.
Most memory-heavy stuff, such as web browsers, easily consume 20-30% more memory on 64-bit mode. That's awful. I just use 32-bit versions of these.
So, what I'm trying to say - I'd do the opposite, something like Java does.
Bit addressability is an interesting concept, though most hardware vendors would be hard-pressed to waste die space on that, and the gains you'd get out of it would be minimal on most cases.