As you noted, the x86_64 sorted out some of the mess.
Personally, I think a big issue is the whole backwards-compatibility thing. It causes all sorts of nastiness, and a complete overhaul of the architecture is impossible because everything depends on it! (Which is one of the reasons the IA-64 never really became a hit.)
I vote we design our own processors, and write a new kernel to boot. ;)
As you noted, the x86_64 sorted out some of the mess.
Personally, I think a big issue is the whole backwards-compatibility thing. It causes all sorts of nastiness, and a complete overhaul of the architecture is impossible because everything depends on it! (Which is one of the reasons the IA-64 never really became a hit.)
I vote we design our own processors, and write a new kernel to boot. ;)