It's not a heavy hitting high base damage weapon and it has no damage increase. Shadow strike is a rarely used special IMO.
Just to give you a better idea... If it was a butcher knife you'd be able to sell it for about 1mill with them mods, as buther knives have disarm and infectious strike two useful pvp specials and no need for damage increase as its not a high damage output weapon, normally good for poisoning death strikers.
Other mods like hit spell/swing speed, would add to the value of these low DMG output weapons and same for high DMG output with armou ignore(kryss/broadsword/katana/spear/leaf blade).
Things that do not add to value are - HIT AREA EFFECT.
Hope this helps.