I think it's good that they're moving away from using bash for things that it doesn't belong in-- like init scripts. /bin/sh should just be a POSIX shell, not bash. If you want bash, ask for it by making your package depend on bash and invoke it explicitly.
> I sure didn't notice the difference, whatever that might be; but I did
> waste time with dpkg-reconfigure to test this.
You probably didn't notice the difference in thousands of other small optimizations people made, either. But added together, they make a difference.
> I'm pretty sure Bash is not unfixable, it is a damn console, not the
> entire kernel.
I'm pretty sure you've never seen the source code to bash.