Because they made things so stupidly powerful that it shouldn't have come to the point where we are complaining about a weapon with that many attributes. I mean look at the 3.5 version that it is based on. That is the iconic weapon as you say. Look at what they have added to it and people are complaining that it is basically vendor trash. What does that say about the power creep that has been going on...and that people have been saying since shroud came out? I know that is another arguement. But at SOME POINT the it has to be reigned in here. Why not just add Holy, holy burst, holy blast, pure good, good burst, good blast, axiomatic, axiomatic burst, axiomatic blast, distruption, greater disruption, greater evil outsider bane, banishing, 4d6 x4 15-20 keen, silver, cold iron while they are at it. That way since it is the weapon of choice for paladins, the one they all want to strive for, they won't need to bother with any other items in the game.
Yes, that was all over the top, and that is the point. How over the top do we need them to go with this weapon? If they called it "gary's sword", would people be up in arms about it? They would say it is an ok weapon....could use a little work with the dice and crit range. But since they kind of envoked a holy avenger title with it, people are saying it is absolute garbage.
Besides, do we know of any hidden effects when it is paired with the matching shield? Personally, I think that would be the better way to go. Ups the damage dice, crit range and crit multiplier by one on each.