This makes sense, I hadn't thought of knowing the hashing method and it being unsalted. Knowing those it would be just as easy to whittle the list down exactly the same way.
Err, not exactly the same way. Sure if you have a rainbow table of all the possible values of the hash construct then it would take a negligible amount of time. Doing the math of all possible values in the Hash space you will quickly see that at this point in time and space it's not plausible to have that.
You may then argue that you can have the value space of all popular passwords, but that isn't going to be any more effective than just trying all of the possible passwords.
You may then argue that you can have the value space of all popular passwords, but that isn't going to be any more effective than just trying all of the possible passwords.