I think it would be absolutely awesome if the assembly output from my C compiler were syntactically-valid and semantically-equivalent C. Among other things, it would enable me to compile it (with a C compiler rather than an assembler) to run on a different CPU architecture. And then I'd just need a disassembler to generate it in the first place.

Unfortunately this isn't possible because you can do a lot of things in assembly that you can't do in C. RET, say.