Personally I wouldn't like to have an Assembler re-arrange my code, specially since the issues you mention can even change between firmware revisions.

On the x86, starting with the 486 and Pentium it wasn't possible any longer to fit all variations on the head.

At least I can't.

The porting I mentioned above was to make a compiler depend only on binutils.

Other than that, my last 100% Assembly application was around 1995.