There was something about the Ethereal prefix itself adding to the equipment quality...
QUOTE(Tenboro @ Oct 17 2009, 08:04)

If you get a superior weapon that rolls as ethereal, it gets a "bonus" to the quality readout that could tip it over as exquisite, but this happens after the thing that makes the proc. And no this isn't fixed on live, but the fix will be not having it apply a bonus like that, so it won't actually have an effect except for on the name and value of the item.
...but if that fix was actually implemented, that wouldn't apply any more. But who knows?