Well, to be fair, it is a minimal upgrade. Even Gugnir unaugmented will beat it without accounting for any use of the defense down or the crit bonus on Shining One (which, I assume isn't significant), and then augs would obviously crush it. The lance is more useful for a SAM or WAR than DRG, and compared to other Ambu weapons you could say DRG got the short end of the stick due to Impulse Drive not being a WS like Evisceration or Savage Blade.
If anything the Shining One just lets you have the best weapon pre REAM for DRG outside of a really well augmented Reienkyo. So that should allow you to weigh your choices.