From a damage standpoint, yes the critical multiplier is better then critical rage and thats the point. Barbarians are good at dealing lots of damage. They are not good at precise hits against vulnerable locations on a target. An increased critical range represents the ability to precisely strike a target. Along with that critical range increase comes the ability for critical abilities to trigger more often which oddly enough makes it better for barbarians to use fairly low damage dealing weapons with powerful critical effects, W/P weapons, banishers, smiters, then to use weapons which deal large amounts of damage (obviously red and purple named mobs don't apply to this particular analysis). This is what disturbs me about the barbarian critical rage enhancement.
Side note:
So I plugged equal barbarians into the DDO weapon damage calculator...both have 40 str, corresponding two-handed fighting feats, etc. One gets increased critical multiplier of +2 (19-20/x5) and the other gets increased critical range of +2 (17-20/x3). Both are using a standard +5 great axe for comparing apples to apples. For me the damage graphs for the two barbarians were exactly the same. Was I doing something wrong or is the average potential damage the same regardless of the way the critical bonus is applied in a basic comparison?