As we already knew the review embargo for Dark Souls 3 lifts on Arpil 4th, 9:01am CEST.
Gamestar could write and publish a finished review about the japanese version of the game right now.
They decide against that because their version has a Day-One patch that the Japanese release version does not have.
This Day-One patch includes over 300 changes from the japanese version (according to Namco Bandai), including technical aspects like framerate, stability, keyboard/mouse support aswell as game mechanical tweaks.